BOUNCE IS BACK

[atvpilot]

Well Guys my last post was regarding a rear end bounce between 45-*48 mph. Well Guess what it's back. I am really getting very disgusted with this whole thing. I went and got diagnosed by the dealer to the tune of $160.00 to tell me the tires were bad. So I go and drop $300. on a discounted set of BFG All Terrian 265/75/16 only to have the problem still there. I called the dealer back and advised them that the problem is still there and I will be returning with the vehicle because there diagnosis was incorrect. I honestly believe nobody knows what the heck is wrong and it is just a shot in the dark. I still think it has something to do with the rear end or drive train. I had the oppurtunity to chat with a guy while on vacation who told me his rear end checked out at 32,000 miles. He told me that his carrier bearing went. Anybody want to offer anything please free to jump in. I have always been a GM man but if I can't this straightend I will definitley be switching to a different mfg.

[Texasoilman44]

Not sure if this helps or not but I seem to remember some kind of service bulletin that addressed and issue with the 2 piece drive shaft. It has been at least a year ago that I saw something on here about it, because I have a slight shake in my truck above 40 mph and I was looking for a fix also. Mine is not unbearable so I just chalked it up to having the 285's on my truck and also having raised the front end to ride level with the rear. If I am not mistaken, the bulletin was to replace the 2 piece drive shaft with a 1 piece drive shaft. Maybe someone else will remember what I am talking about.

Kind regards,

Kevin

[atvpilot]

thanks Kevin, the last time I had it in they did an EVA test on it and stated the driveshaft was ok and that it was the 285"s that were causing the problem of the rear end bouncing like a basketball. So I went down to 265's and I still have the problem. I will do an online search of GMC Truck service bulitens.

[Spoolin'It]

Atvpilot,
Do yourself a favor tomorrow, pull out the back shocks and see if there's anything left to them. I had the same problem after switching to BFG's at 15k miles,tried rotating tires, etc. problem was still there. Turns out it was the shocks. I couldn't believe how shot the crappy factory shocks were at 15k considering I don't tow or haul much. Switched to Bilsteins and haven't had a problem since, now at 33k.

[atvpilot]

Spoolin it,
I had that thought this afternoon myself. I had to teach an atv safety course this am. I had my 22 ft Haulmark enclosed trlr hooked to the truck. After I got home I dropped the trailer and later drove the truck to work and that sucker was bouncing the worse it has ever even if I hit the smallest bump. I will take a look at that tomorrow before I go back into work. Do you recomend the Blistens or are there others would also use? The truck has 46,000 miles on it and the previous owner used to haul a 5er. I haul a 30ft TT or my enclosed Haulmark.
Also would this problem effect the handling of a trailer when being towed. I had a terrible problem with either of my trailers swaying and I have the proper hitch set up???? Thanks much ;)

[Spoolin'It]

At 46k I will guarantee they are shot. We have 2 HD gassers at work with around 30k each that both are desperately in need of shocks.
I am happy with the Bilsteins, if you look in other posts it seems they are the shock of choice on the board. I also had them on my 95 half-ton, at 80k they were still going like new.
As far as the trailer sway I would say shot shocks would definately not help the situation.
If you are towing that much you should replace all 4 shocks even if its not the problem, the improvement in ride quality is worth the money.

[atvpilot]

thanks Spoolin it. I have an appointment with the dealer on Monday. I will mention this to them but probably will not have them replace them althought I should make them reimburse me the 159.00 charge they got me for to tell me the rear axle was hopping like a basketball. They said it was the tires.
Thanks again ;)

[Boonbltz]

I got a set of 4 Bilsteins at kennedy diesel for 260.00 free shipping

[Runaway]

I had the bounce on mine until I replaced the shocks@ 39,000 miles. H
Nothing left of either shock! No bounce no more, still stock SteelTex @ 44,000 miles.

[atvpilot]

Well Guys,
I got my truck back Monday night and attached to the bill was a service bulletin . The way it was explained to me was there are different frequncy or vibrations that run through the truck and tires. It was told when these frequencies cross each other this is what causes the chatter fronm the rear of the truck. I did have them check the shocks and they said they are ok. I have just spent in the last 8 months over $800.00 in tires and I didn't want to spend anymore money on shocks if I didn't have to . I think the heading at the service bulletin said SUSPENSION VIBRATION/ FRAME BEAMING. If anybody would like a copy I would be more than happy to fax you a copy, Oh yea and by the way they say there is no positive fix. So the way I understand this is if you run an all terrain tire which some have an semi aggressive tread(BFG All-Terrian which I have) you will always have this annoying problem. If you run a regular street tire (and now I know why they put those Michelin LTX4 which have no traction whatsoever) then you may not have this problem. Pretty discouraging. You spend a small fortune for one of these vehicles, and for what????? To go out and drive around and have that annoying vibration come right through the truck and it shakes you . :mad: :( . I haven't driven a Ford latley but I just might.

[Spoolin'It]

Yeah they checked the shocks, that means there was no oil leaking down the side of the shock and dripping on their heads. I highly doubt they unbolted the shocks and checked if there was any compression/rebound left. My shocks showed no sign of an external leak or failure yet there was very little left to them. Also its impossible to do a "bounce" test on the rear of these trucks due to the stiff springs.
I kind of suspected GM was on the hairy edge of balancing these trucks based on my own experience and the harmonic dampner on the differential pinon yoke was a good clue. That also explains the one and only one choice of tire size for these trucks.

I'm telling you I had the exact same problem as you, the rear felt like it wanted to bounce right out of the back of the truck, also changed lanes when hitting a bump. It started right after changing to BFG tires and unfortunately I had to live with it because the Bilstein rears were on national backorder for several months. The problem was solved immediately after changing the shocks and I haven't even seen a hint of vibration in the 18k since.
Now if GM would smarten up and put a check box for Bilstein shocks right on the order sheet like they did for the older half- ton trucks(automatically included if you got a Z71 package), we all wouldn't have to be reaching into our pockets again to fix their mistakes.

[atvpilot]

Spoolin it thanks for the reply, I guess it's time to start saving for the shocks.I know you said they are the Bilsteins. I have a 2002/2500HD CC D/A SB. Is there acertain model I should be ordering for my truck???? Let me know and again thanks for the feedback.

[Spoolin'It]

As far as I know all 2500's use the same shock reguardless of cab/bed configuration.

[atvpilot]

thanks Spoolin it. smile.gif

[tophog]

I almost started crying when I came across this post ...as I thought I was reading my own story.

2003 2500 HD Crew Cab 4x4 LT, only 15K miles. I've had the following wheel/tire combos since new:

1) Stock tires/wheels (for about 1 week)
2) BF AT KO's (265's) on stock wheels (3K miles)
3) BF AT KO's (315-70R17's on Weld Evo Renegades (8K miles)
4) Weld 16x8 wheels with Toyo Open Country A/Ts (295-75R16's). Present configuration.

I never had a vibration one until I put about 5K miles on the Toyo's. Had them rotated and developed a rear vibration/hop from 40-50 mph. tire shop (Les Schwab her in Oregon) re-balanced them ... were out a little but not much. Still had vibration/hop. The tires where then road-forced-balanced ... found bad left rear. RFB showed 178lbs ...was suppose to be under 40 lbs. Replaced with new tire. Still have the vibration as of today!

I feel your pain! I should add my truck has a 4" Rancho lift but I've had that all checked out, etc. All started when tires were rotated. Ironically the Les Schwab employee that did the work drove my truck and said his 04 2500 HD LLY is doing the exact same thing and he has balanced/rotated his tires multiple times with no luck.

I am so frustrated I am about ready to revert back to my 315's which road like glass but now I'm not so sure it will solve the problem. The only thing I would add is I've had vibration problems with Toyo's in the past and went thru the same thing ...swapped out with Michelin's and vibration disappeared. Since I liked the Toyo's I thought I would give them a second try but now biting my tongue even though the vibration/hop seems to be something other then tire/wheel combos.

Sorry so long ...just venting.

BTW, new Bilsteen's were installed with the lift. The Stainless steel ones ..not sure what series they are.

[ 08-08-2004, 08:03 PM: Message edited by: tophog ]

[Scott Duprey]

I have a 3500 with simular issues. I just tired wheel balancers and am getting ready to return to the company. Those made the vibration worse and darn near unbearable.

I have no idea what to try next. 60k on mine with the 2nd set of tires on it. After trying several different things I am starting to think it is a drive shaft issue.

What I don't understand is why others don't have this problem as well. Am I the only one with a 1 ton that has this issue.

[tophog]

Update:

Took truck back to Les Schwab today. They drove it and said it vibrates from 40-63 mph as I told them it did. I told them I was done with the Toyo

[tophog]

Found today when I grab the top of the PS rear tire and rock it in/out I hear a "clunk" either from hub or rear-end. I do not get the clunk from the driver's side. Just so happens the guy at Schwab said the vibe is definately PS rear. The question is if this is "normal" or a sign of a bearing/bushing gone bad or perhaps something in the rear end? My wishful thinking is bearing/bushing but can't understand something like this with 15K on the truck. Will post more when I find out more ...

[Modified]

Could this be another case of

[tophog]

That would be good to know ...if the dry spline deal applies also to the one-piece. I heard someone took there truck in to have the splines greased and the dealer told them they weren't greasable smile.gif and if the seals/paint on the ujoints were broken or tampered with warranty would be voided on the driveline, ujoints, etc. That won't prevent me from pulling mine if it might help ...Another one of those "dealer" stories.

He&^, at this point I'll try anything. I had my entire truck inspected over the last three days and various tests done in effort to isolate/identify the vibration ...4 guys worked on it together (tag-team) and they found zippo..nothing wrong other then the fact they said my entire motor/transmission shakes at the speed I feel the vibration the most. They called it "abnormal" and told me I should take into dealer. Mounts were fine. they also thought I should try unhooking the Juice to see if that made any difference which I did tonight but haven't drove yet.

What about loose flywheel or torque converter bolts? I seem to recall a problem with one or the other coming loose. If this could be a possibility (might be the problem if motor/tranny are shaking?) is it very hard to check?

[tophog]

VIBRATION SOLVED!!!

I found the source of the vibration today smile.gif After thinking more about what Les Schwab said yesterday about the motor/tranny vibrating

[tophog]

Vibration NOT Solved ...

I spoke prematurely ... I take back all the above as of this morning after driving truck to work. IT STILL VIBRATES/SHAKES!!!! I guess I should have drove it more then 1/2 mile yesterday. I guess this problem is driving me MAD to the point where I am trying to convince myself the probelm is gone when it's not ... DAMN!&%#?

[tophog]

Vibrated home this afternoon. I discovered I can reproduce the shake/vibration sitting in my driveway by simply increasing throttle. At about 1K rpm you can feel the exact same vibration ...up around 1400-1500 you can really feel it ...you can see the motor shake as well as the seats shake. It's much more pronounced under load going down the road though ...but still very noticable standing still, in park.

Thoughts?

[sonofagun]

Guys,

I'd definitely get Bilsteins on these trucks if you don't already have them. I put Alcoa rims on my 2004 3500 and Michelin LTX tires and the Bilsteins .. all when new. The steel rims on a 3500 look like cr#$ anyway and they are often not well balanced. I run the tow version Juice and I have no vibration at all. I did the same thing on my '01 2500 and had no vibration there over the 3 years I owned it. Check the center drive shaft bearing if you have the 2 piece.

tophog,

If it vibrates sitting still it may well be linked to: motor mounts, trans mount, loose or misalligned trans to motor. Sitting and vibrating has to come from the motor/trans through the frame. There was an issue early on where the torque convertor bolts worked lose and caused serious grief. Check those too, they may be loose enough to cause this but not too loose to cause damage yet.

Good luck with this issue,
Bob

[tophog]

It's going on it's maiden voyage to dealer first thing Thurs. morning. I'm tired of guessing and will let the dealer see if they can figure it out. I am aware of the torque converter bolts loosening up on the 01's and was one of the first things I was wondering ...

I had my dad drive it today as he's drove diesels for years and he, as well as a few others thinks it's an engine miss, possibly injectors or timing problem...almost feels like a dead cyl. Knowing my luck I know it will be something bad ...like injectors. Thing is it hasn't smoked, starts up fine, I thought it has run fine ...but have noticed it seems a little noiser then it used to be.

I'll post more once the dealer has diagnosed it.

[atvpilot]

Hey Guys,
I can't thank you guys enough for taking an interest. Like I said, I am really dissapointed in a truck that I have wanted since they ame out with this combo. Now I am ready to trade it for a Ford 2500 or a Subaru WRX and forget all about owning another GMC(Generally More Cash) product. My truck goes into the shop on Monday for the steering column recall and I have spoken to the tech as to what to expect whenI get there. I already warned him about any bulls### excuses or stories. I told him that I had the notice about the launch shudder and I want something done about it. What little I know about the mechanics of the truck is this, It appears like something is hanging up or binding and the added friction of that action is putting a strain on the driveline causing it to work harder. When I had the shocks installed at my private garage, mechanic the noticed that the univewrsal between the 2 drive shafts were looking a litte shabby.They said something about the rubber looked like it was peeling off, whatever that means. Does anybody know if the gas 2500 hd are having the same problem???????
Sorry it took so long for me to get back to this post but without email notification like the other sites,I didn't think anybody else was responding. Hey just had a thought how about the Kennedy's diesel guy. You have any input on this mysterious Duramax dilema?????
Pilot
ps ANYBODY GOT THE PHONE NUMBER TO COMPLAIN TO GM ABOUT THIS PROBLEM.We should all call and flood the damn phones.

[ 08-18-2004, 05:12 PM: Message edited by: atvpilot ]

[atvpilot]

Hey Guys,
I have been thinking the past couple of days and there are alot of similarities. These trucks are all Dmaxies,allison trannies,posi traction. Anybody think of anything else??? There has to be a common denominator here to be causing the same problem. :confused:

[tophog]

Well, truck made it's "maiden" voyage home from dealer ...the last might I add. Had it for 2 days, no codes set so no problem they claim. Tech did drive and admitted it vibrates from 45+, but vibration in Park reving to 1400-1500 is normal ...said he checked another truck and it did the same thing ...and thinks rear u-joint is bad. NOT! They didn't have one ...I remarked "Must be a popular item in 15K mile trucks" which resulted in a "go to h&%L look". The ticket said they did loosen/retighten motor/tranny mounts, blah blah blah and found nothing out of the norm. I asked about flywheel/torque converter and all I got was "Oh, it's fine ...". So I'm back to driving a $45K vibration truck ...until I get frustrated enough to purchase a $1.00 forsale sign. I guess I'll go ahead and buy some Ground Hawg tires to mask the vibration. I shouldn't be too upset ...it's more or less what I expected before I took it in. Guess I'll drive it with Juice Level 4 until something breaks or falls apart.

[tophog]

A summary of the last week. Dealer said motor, tranny were fine, no codes, checked all mounts, etc. They did drive and felt vibration (note, my problem is not a "hop" but a vibration throughout the truck). They said rear u-joint was "binding" and needed to be replaced. I asked @ 15K miles? Service mgr said "yes, seen it before". I played along at that point. Of course they had to order one ... and checked it myself, u-joint looks/feels perfect.

The dealer still hasn't called me back about the rear ujoint so I assume it hasn't come in yet. I had the driveline checked today by a driveline shop. They just called and told me it has .025 runout and they considered it bad @ .020. They said the u-joints were fine though!? say what?

What am I suppose to make of all of this? Is there a GM spec on the driveline runout? With the driveline being so long perhaps the driveline would still be considered "good" using a GM or Spicer spec?

Should I contact the dealer again and tell them about the driveline check or would I get my hands slapped for that? I just want my truck to quit vibrating.

thoughts?

[tophog]

Ok "Bouncing" friends. Found this on the RV.net forum ...guys with same problem, same story, etc. This almost makes me laugh ...anyone know where sandbags are on sale? He&%, guess I'll try it before I set my truck on fire. Below is a snippet from the latest post today. I've also listed the URL if you want to read more.

------------------------
Ok , Took truck to shop today and we did what the bulletin said and put bags of sand (350 lbs.) in back of truck between tailgate and rear wheel wells. It completely stopped the vibration. The Bulletin said , "no further attempts to repair" as this is normal.
Bull! It can't be normal to have to ride around with sandbags in the truck to keep it from shaking you all over ther place! They are not even trying to fix it.

This will be the last GM truck I'll buy until they can do better!

Funny , the Fords dont do it. Its too bad , I really love my truck and hate that I just have to accept this "Frame Beaming/vibration" as normal. They said my carrier bearing was ok, funny it was trashed when I had it on the rack...? OH well , life will go on. Thanks for all your input and time...db.

http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/14185986/srt/pa/pging/1/page/1.cfm

This vibration thing sadly makes me think of the GM 6.0 piston slap problem. Been there done that too ...was the truck I had before the Duramax.

[DmaxMaverick]

If it were normal and acceptable, they would all do it.

It could be caused by carrier bearing, U-joint, shocks, bent axle, ring & pinion, wheel bearing, sticking caliper, warped or out of round wheel/tire, and the list goes on. It is up to the dealer to make it right. Sand bags are not the answer. Same as the dealer telling you to turn up the radio to drown out a noise.

[dieseldealer]

Since the problem started after the Toyos, Did you get the BFG tires back on?? Do you still have the stock tires and rims?? I would want to drive the truck myself with either the stock rims and tires or the BFG tires. Who installed the lift kit?? Have you had him check out the installation. As far as, "it is up to the dealer to make it right", Did the dealer install the aftermarket wheels, tires and liftkit?? If so, then it is up to him to get it right.

[tophog]

I had 315/70R-17 BF's on for 14K miles and did not notice "any" vibration. I went to Toyo's and ran those and didn't notice any vibration for the first 5K miles. Had them rotated and that's when I noticed the vibration so we naturally assumed it was related to rotation.

After 2 days and swapping out my tires wheels with 2-3 "different" sets of tires/wheels INCLUDING OEM wheels ... did absolutely NOTHING to change/alter the vibration. This has been the same case for others with the same vibration. After this type of time-consuming testing it is very aggravating to hear "it's a tire/wheel problem".

Almost in every case, the vibration has started after 10K miles. Note, no one has had the vibration since new, including myself. Like I said, my truck rode/drove like glass for the first 14K miles. Yes, I have a lift and it's all been checked out by the same tire/wheel shop (Les Schwab) who worked on my truck for 3 days trying to identify the vibration problem ...and finally threw in the towel.

If I was the only person with the problem and the only person who has gone thru the same process of swapping tires/wheels, driveline, etc. with the exact same symptoms then I would acknowledge the lift could be the problem however I would also argue there are many others with the same lift/tires/wheels, etc. with no vibration ...just as there are other stock trucks with no vibration. I am back to running brand new BF KO's in the 295/75R-16 size ...all road forced balanced on Hunter 9700.

There's the other aspect of all this related to the GM PI that specifically addresses a vibration problem between 40-50 mph called "Frame beaming/vibration" ...with apparently no fix. Actually GM's fix is throwing 350 lbs of sand in the bed. GM's response is basically we don't know exactly why short bed crew cab pickups do this but they do and we don't know how to fix it ...so live with it.

If there is a tech in the house could you please post PIT3009 issued June 10 2004 so others can read this?

[SHOPMAN426]

Hey Tophog,

It looks as if you have tried stock wheeels and tires. Since I live so close I would offer up may truck and stock wheels for testing. I run Weld Wheels with 265 75 16R's. My stock rims have studded 265's as well. We could even mount your 295's and wheels on my truck for a test. Don't know if this would be any help, but the offer is on the table.

Shopman426.
Mike. :cool:

[tophog]

SHOPMAN426, I appreciate the offer but have my brother's 2004 2500 HD Crew Cab at my disposal for parts swapping. We have already tried his tire/wheels with no luck as we also put mine on his truck and it drives like glass. This didn't surprise me due to the swapping Les Schwab had done already. I think continuing to go down the tires/wheels path would be stupid in my case based on the testing done to date.

I have an appt. at another dealer Tue morning. Surprisingly the svr mgr was very eager to listen to the problem, the testing that's been done to date as well as the PI issued by GM regarding the Frame beaming/vibration ... he pulled it up on his system once I gave him the number and thought it was complete BS that GM expects guys to haul 350 lbs of sand around.

Also he didn't balk at all when I told him about the driveline testing done at a driveline shop as I think he is very familiar with the driveline shop (Six States) as they are close to him and knows they know their sh&^. I went ahead and had the driveline shop put in new Spicer U-joints (with zerk fitting) to completely eliminate U-joints. Still need to pick it up and install but don't expect any change in vibration.

I will put some weight in the rear later today just to see if it does help ...then let the dealer look at it and see what they come up with. Not expecting any miracles ...perhaps the fix is reshimming the rear diff to change the angle of the pinion/driveshaft ...if that can be done. Perhaps GM knows that is the fix but doesn't want to recall trucks and spend the money to make it right. Who knows ...

You said we were close ...where are you located?

[SHOPMAN426]

Just up the freeway in Tigard, 217 and I 5.

Shopman426.
Mike.

[atvpilot]

Hey Guys,
Well ya know that bulliten about the steering shaft. Well I was under the impression it was a recall. They don't tell me this until the fix i tthen tell me I owe them $194. So now I got to try to get my money back from GMC.
So while I leave the truck for the whole day they come back and tell me that it's the rear u joints are going bad and possibly the carrier bearing. I say baloney. GMC has screwed up and they are scrambling to correcta problem they don't know what they have. I have know a guy that is a mechanical engineer. He states tat it might be a misaligned driveline. The dealer says no that is impossible. Next truck will not be a GMC until they can start being resoponsible for what they build. :mad:

[tophog]

atvpilot, the dealer is grasping at straws. After all the crap I've gone thru the last 2 weeks I finally decided to put some weight in the bed. All I had was 300 lbs from may cast iron weight set. Took it for a spin and vibration was basically gone. The "Frame beaming/vibration" PI (Preliminary Information) bulletin issued in June states to add 350-400 lbs. I figure with another 100 lbs or so my vibration would be gone completely ...however carrying around 400 lbs is not a solution IMO.

I had bought air bags and never installed them until tonight as I thought it couldn't hurt anything. With 10 lbs in the bags (minimum) and no weight in rear and can definately tell a BIG improvement ...again, vibration "almost" gone or barely noticable.

My hunch, and about my last one, is that the vibration could most likely be solved by shimming the rear differential by placing 1 or 2 degree shims between leaf spring and axle which would alter the pinion/driveshaft angle. I think the pinion needs to come up a little based on the fact adding weight in the rear most likely makes the pinion come up some which makes the vibration disappear. I may have this backwards regarding the pinion going up/down but you get the idea.

I had my driveline checked out yesterday and it was fine ..including the u-joints. I truely think at this point the problem is related to the pinion/driveshaft angle. why some trucks have the problem and majority don't is beyond me but again you always here the saying "every truck is different". It appears you and I got the "black sheep" GM/GMC's. smile.gif

[atvpilot]

Tophog,
This is exactly what a friend of mine was saying the other night about changing the angle of the rear end and the drive shaft. I will speak to my mechanic tomorrow and show him this post. The only problem I have about carrying extra weight in the back is the fact if you are involved in an accident, that is just more stuff flying around. Unless you pour concrete in the bed, :D but then you cut into your fuel mileage. Maybe we should start the next post as to what is the best thing to carry in the bed to get rid of the vibration. I was thinking all the damn money I have spent so far in change :mad: . That should weight it down pretty good. Tophog again thanks for the info.
pilot

[tophog]

After viewing the angle of my differential/pinion mine looks as though it's tilted up more then it should be ...in theory the pinion should be level/parallel with ground as well as the output shaft of the transfer case where both the differential pinion and transfercase planes are parallel with each other. In other words if you draw an imaginary line straight out from pinion and transfer case shaft ...both should be parallel with each other and the ground...and the driveshaft angle no more then 3 degrees. this is what I read on several differential-related web sites and makes sense. I'm just baffled as to what, if anything, the weight is doing to the pinion angle...perhaps it's doing nothing but absorbing the vibration in which case altering the driveshaft angle would do nothing.

[atvpilot]

morning Tophog,
Well I just went down to yhe local scrape yard to price out a metal plate for the back of my truck,$550.00 OUCH. While I was there I was talking to there heavy equipment mechanic. He basically said the same thing you said previously as well as my mechanical engineer friend said. It sounds as if the drivtrain is out of alignment. I am going to call my mechanic now and see if theses guys can shim it and try that if not, he has a transmission guys thaty has done work for him. I'll let ya know. I look at it this way, I dropped alot of money on this truck and have it set up the I want and I am not going to take the ignorant excuses from GM dealers because the enginers that designed thses truck had their head up their butt and screwd somethung up.
Pilot :mad:

UPDATE
Just talked to my tire guy. He is telling me that the best way to go is ti weight down the back of the truck. He told me the reason why it is probably set up that way is the trucks are designed for heavy loads, so when you load it up it aligns the driv line. So now I am in search of a flat sheet of steel so I can still use the bed of truck but not get that bounce. I am going to put my atv in the back over the weekend and see what happens. It's about 650 lbs. I'll let you know.

[ 08-27-2004, 06:50 AM: Message edited by: atvpilot ]

[tophog]

Originally posted by atvpilot:
morning Tophog,
Well I just went down to yhe local scrape yard to price out a metal plate for the back of my truck,$550.00 OUCH. While I was there I was talking to there heavy equipment mechanic. He basically said the same thing you said previously as well as my mechanical engineer friend said. It sounds as if the drivtrain is out of alignment. I am going to call my mechanic now and see if theses guys can shim it and try that if not, he has a transmission guys thaty has done work for him. I'll let ya know. I look at it this way, I dropped alot of money on this truck and have it set up the I want and I am not going to take the ignorant excuses from GM dealers because the enginers that designed thses truck had their head up their butt and screwd somethung up.
Pilot :mad: Good luck! I will be real curious to the results of whatever you do, especially the shimming. Unfortunately I think we are on our own to solve this ...if it can be solved. I sure hope so, else mine won't be around long.

What type of metal was your quote for? I too was wondering how much 2-4 thick slabs of steel would cost ... I'd be interested in 100 lb rectangular pieces I could place on the sides behind the fender wells. Definately don't want big-ass bags of sand. Ultimately the dealer should pay for the "ballast" smile.gif

[tophog]

I have (4) 75 lb sandbags in the back of my truck today and the vibration is "almost" gone. Without the sandbags you'd have a hard time drinking a cup of coffee without a straw.

atvpilot, I would really like a copy of the PIT3009 bulletin. Is there any way you can email me a scanned copy or fax to: 1-501-643-9835

[tophog]

BTW, I don't buy the "all these trucks will ride like this as they are made for pulling/towing" ... this is my 3rd 2500 HD Duramax and my previous 2 trucks drove/rode very smooth. This one is a martini shaker at 45+ without 300 lbs in the bed. Hell, everyone that rides in it give me a funny look above 45 mph and ask "what's that?".

[atvpilot]

tophog,
The qoute was for a flat piece steel 5 ft long by 4ft wide. Just big enough to lay between the wheel wells from in front of my bed box to the back.

I will fax you a copy tonight around 1130 when I get home from work. Would that work for you?
Also I stopped at another scrape yard and a guy wanted to seel me a 3 1/2 foot round piece of scrape metal for $200.00. I told him I would get back to him. I think I spent enough money.
Pilot

[MTTwister]

So this is mostly a problem with the Short box - slightly shorter wheelbase than the long box? Putting more of a "stress" on the Pinion angle - u-joint area than the longer configuration? Longer is just long enough to take the stress off that "assembly"? ( Assumption being that the axle has the same mounting angle in both outfits.)

[tophog]

atvpilot, anytime on the fax will work as it's an internet fax and I'll get it via email. Thanks, I appreciate it. I picked up 4 - 75 lb bags of sand today at a tire shop. Made world of difference but not fond of the space it consumes in the bed.

I think the problem is "mostly" the crew cab short bed however I've read reports of others experiencing the same thing in extended cab short box as well as crew cab long box. A local friend has an 04 2500 HD crew cab long box with the exact same problem.

[atvpilot]

Tophog,
Sorry I didn't send it last night, was a little preoccupied with life, if ya know what I mean. It's on it's on way. I'll be checking back with you guys once I get to work later today.
Pilot

[tophog]

Hey, no problem. Received it this morning and have posted on Internet for others to read. Here are the links. This bulletin reminds me of the piston slap problem in the 6.0's ... GM calling a design defect "normal". This vibration thing MUST be addressed. I think we need to establish a web site for owners to collect information and put the pressure on GM otherwise they will continue to do nothing.

Perhaps the new GM tagline should be ..."Have you driven a "vibrator" lately? smile.gif Just think about the 6.0 owners ...they have a vibrator and a knocker.

.JPG format

http://home.comcast.net/~tophog/duramax/PIT3009.jpg

.TIF format

http://home.comcast.net/~tophog/duramax/PIT3009.tif

[Turbo Al]

Wow,
this thread brings back alot of bad memories from my 1991 S-15 Jimmy. The fix for that one was to get rid of it! Through their 1-800 cust assistance I got some answers to what I already suspected -- somewhere along the line the truck had been dropped and they still had the nerve to sell it! I don't know how they accessed the records for this truck but they did and with a $$$ credit in hand they also Checked out my planned purchase (the 1993 6.5 TD) before I bought it. So moral of story see if cust service will do a check for any mishaps before delivery.

Second I do run deep lug snow tires (60's) with NO vibration at all -- they are Cooper Discoverer. I do have appox 180 lbs of extra weight on the back of truck (new "Ranch Hand" bumper) plus another 50lbs of headacke rack and rails -- alot better options than 350 lbs of sand, New shocks all around at about 22,000 miles.
I do not and have not ever run any power boxes.

Good luck with your bad vibes.

Al

[atvpilot]

Tophog
I couldn't agree with you more. Gm has to start answering for their inherent design problems.

[cowboywildbill]

Maybe you could get the correct pinion angle by temporarly shimming the rear by trying this. Shim it where the springs meet the shoes that are welded on axle housings. Run it and see if it helps. And if it does, maybe changing length the shakles can help change the angle, or some type of permanet shim and longer pins for the springs might work. Just a thought. I know how frustrating these things can be. And it is usually something simple that causes the problems, but finding it takes a lot of trial and error. That's why I love this forum, it saves a lot of that hassel for all of us sometimes. Good luck, It is sad that you have to do all of the scientific work that GM should do. And I bet someone at GM knows about the condition & what the cause and cure is, but they don't see it on enough vehicles or have enough complaints and feel they don't have to deal with the issue. Good luck!

[atvpilot]

Cowboy Wild Bill;
Thanks for the info . I have already spoken to a couple of mechanics and they won't even touch it. They say it is alot easier to put a sheet of steel in the back and let it go at that. I kinda agree, but the steel is going to cost between $200. and $500. .looks like GM has done it again. I am seriously thinking of going to the consumer media about this. :mad:

[carco]

I don't know how much Line-x of Rhino bed lineing weighs but you can bet it will add some weight and serve good additional purposes. The liner installers should have a basic weight per sq ft or per bed estimate. I own a repair shop light to HD vehicles and probably not want to take on a spring angle shim project, but a spring shop, body upfitter, frame shop, that modify trucks and has an alignment rack may have no problem with this shim project. We have a spring shop in the Cinn, Oh. area that probly would. bob .........

[atvpilot]

Carco,
Bob thanks for the info . I actually installed my own Rihno liner in my truck as soon as I got it. The Line-x was more than I wanted to spend. Btw I like your chioce of atv's I own one with a heel clicker clutch kit. What a difference.
pilot

[tophog]

I already have LineX ... I could actually tell a very noticable difference between 225 lbs (3 75 lb bags of sand) and 4 bags (300 lbs). Tried 3 bags yesterday and could really feel the vibration ...not as bad without any sand but still very noticable. Added the 4th bag and the vibration "almost" is gone. I'm sure another bag or 2 would do the trick but I'm not going to haul around a bed of sand bags indefinately ...I actually use the bed of my truck to haul things. heck, at this point I need airbags to level the truck.

I think experimenting with shims is the logical next-step for me ...it's just getting the time to do it and the right shims. Really need to put truck on lift or jack stands and support rear diff with jack to do it right.

I noticed my pinion points upward rather then sraight out (parallel with ground). From reading on various driveline web sites and viewing picts all the information says the pinion should point straight forward, parallel with ground ...not upward. I don't have any fancy tools like an inclinometer so I'm just going from sight. I would venture a guess and say I would want to shim the differential to point the pinion down more ... not up.

[tophog]

I think at a minimum GM should pay for the rear "ballast" required to keep their truck from vibrating. smile.gif

[DmaxMaverick]

If your truck is stock height with no suspension mod's, ignore this post and get the dealer to FIX an obviously defective vehicle.


For those of you with suspension mod's....
I'm sorry, guys. You are pointing your finger in the wrong direction.

GM is only responsible for defects on UNMODIFIED vehicles. When you do ANYTHING to alter the original design, you assume any and all conditions that accompany it. This includes a Rancho 4" lift. Just because it says "Rancho" doesn't mean it is an end-all to problems.

I am not saying that GM is completely innocent, but if you got a SM to look at it at all is way more than their policy allows. Unfortunately, lifts work in some trucks and not others. A well engineered lift kit will take this into account and design the kit to accomodate it. Many kits just include blocks and no engineering to back them up. Pinion angles are not a new science. Neither are spring wrap issues. As with Tophog, you may have received/installed a good kit from Rancho and it is a problem with GM Design. GM will not offer much in the way of tech support without an accompanying bill for services. If you had the problem before the lift, it's too late now to take it up with them.

For the money you are considering to add "ballast", which I think is the way wrong approach (other than diagnosis properties), spend that money on "high angle, high performance CV joints and aftermarket/re-arch'd springs. Ditch the blocks. They come in different configurations, depending on what you expect your angles to be. The price goes up with higher angles, but you will only need the tamest of these animals. All you need to do is aquire the CV's and have a good driveline-capable machine shop allign and mount them. If you have an aluminum "telephone pole" shaft, you would have to consult them on what the best route would be.

Atvpilot
I reall hope GM steps up and does what they are obligated to do. Vibration at any speed is not acceptable. According to the bulletin, the "ballast" is only intended as a diagnostic tool, and not a solution. The bulletin is only a suggestive route of action, not a final remedy. Insist they get it right.

[atvpilot]

Thanks Damx Maverick.
So afetr reading you post and what you are saying about the pinion angle, would going from a 245 to a 265 tire effect the problem or angle??? I will be calling GM Customer service soon. It's just to bad they make such awesome truck but somebody dropped the ball along the way and I really don't want to spend anymore money unless I get so disgusted and go to a FORD.

[tophog]

What most people don't understand for whatever reason is most lifts, including the Rancho 4" lift retains the factory OEM driveline angles. If you were to measure the angles on my truck compared to a stock truck I think you would find them nearly identical ...so let's not mislead others by using terms like "high angle", "CV joints", etc. when there is literally no difference in angles. This is one of the main misperceptions with lift kits and you will find "most" people find a lifted truck rides/drives much better then a stock truck.

Regardless of dealer perceptions on lift kits I have no doubt atvpilot's problem is the same as mine (just read all the crap we've both tried in eliminating the vibration) ...thus the reason I want him to get his truck fixed via normal channels (dealer) so I know how to fix mine ...since dealers throw up the white flag as soon as they see a lift kit.

So ATVPilot, flush the GM bulletin down the toilet and make them fix your truck smile.gif

[tophog]

atvpilot, was curious if you tried jacking your rear diff off ground and seeing if truck vibrates in gear, under load?

When I do this my truck is glass smooth thru 75 mph ... it's just going down the road it vibrates.

After driving my truck the last few days with 300 lbs of sand bags in the rear I can accurately say the weight has not completely solved my vibration. I can still feel it alot, although not as pronounced. Still unsat. I'm going to order some shims and experiment with the pinion angle next. Just turned 16K this weekend smile.gif

[DmaxMaverick]

Tophog

I don't know where you got your info, but it is not correct.

The major concern with IFS trucks and a lift is CV angles on the FRONT end. The Rancho kit lowers the entire front diff to maintain the angles, to the CV's ONLY.
The propeller shaft angles (both) DO change,unless you have had the engine/tranny dropped 4". I dont' think the kit lowers the engine/tranny. If you didn't have the problem before the lift, and have it now, I would suspect the changes are your problem. Do you have a shorbed? Do you have a two-piece rear driveshaft (you should)? If you do, then your rear shaft angle will be increased considerably. Read on. The following suggestions may apply to you also.

atvpilot
That advice (High angle CV joints) was intended for mod'd trucks only. If you have no lift, pay it no mind.
Changing from the OEM tires to 265's will have zero effect on U-joint angles.

Most of these replies are just bitching at GM for the design, which gets you no closer to a solution. You need to work the problem. Perhaps I can help.

Your truck is a Crewcab, shortbed 4X4, right?
You have a two piece driveshaft, right?
The solution may be more simple than you think.
There is a recall (silent) for these trucks. I'm surprised your dealer didn't at least pursue it.
The two piece shafts, in excab longbeds and crewcab shorbeds have an known issue they are calling "launch sudder" that occurs in some trucks. You didn't mention this in your posts. The launch shudder conditions could extend to other conditions, such as low speeds (40~ MPH).

The fix for this is to replace your 2 piece shaft with a single shaft. This is known to cure the launch shudder, and may cure your problem. GM will fund the repair.

MP (I think) posted the bulletin at one time. Try to find it and compare it to your situation.

If your problem is related, it should fix it. If it isn't related, but you have a bad shaft (regardles of what they told you), it should fix it.
Good luck.

[tophog]

I have a short bed crew cab and it has the one piece drive shaft. As far as I know all 03+ have the single-piece drive shaft.

My brother has an 04, stock. The angles of his drive shaft/CV's don't look much different then mine. In fact you can view mine via the link in the sig.

The lift has been on the first 14,000 miles with zero problems. Like I said before it started vibrating around 15K miles ...just turned 16K miles.

I cannot imagine a lift-kit mysteriously causing a vibration after 14K miles just like I can't see anything other then tires/wheels, ujoints, or something that "Moves" or goes "roundy roundy" causing a problem.

The tire shop has tried 2-3 different sets of tires/wheels with no change in vibration. Dealer checked motor/tranny mounts and said engine had no codes. Dealer stated my rear ujoint was "binding" when it looked fine. I removed drive shaft and had it checked out at a reputable drive-line shop. They told me the u-joints were perfectly fine and there was around .025 runout on the driveshaft which I didn't take to be much at all on a 7-foot long telephone pole looking driveshaft.

Les Schwab even went as far as placing dial-indicators on rotors, etc. to measure run-out. They didnt' find anything out of the norm. Everyone, including myself is at a loss. Driving home today from work (45 miles) was all I could do. Even with the weight in the rear it still vibrates significantly.

I plan to put my brothers stock tires/wheels off his 04 on my truck within the next few days to see if that makes any difference. Based on what the tire shop said they tried I don't have a lot of faith it will change anything.

Here are some picts of the lift and my cv angles, etc.
http://home.comcast.net/~tophog/duramax/images/rancho_lift/rancho_lift.htm

Here is the Rancho info.
http://www.gorancho.com/products/chevrolet_1.stm

If you have any ideas as to what else i might check I'm all ears.

[atvpilot]

Dmax MAverick,
Actually the service writer at the dealership told me about that service advisory. He told me seeing that I would have to pay for it($700.00-$800.00) because I have 48,000 on the truck he really didn't want to go that route. So I guess I might do one of 2 things, get rid of the truck and buy a ford or just stop towing trailers and go to a subaru. Like Top hog,I really don't like tying up the bed of my truck hauling weight around to straighten out the mis design of the GREAT GM engineers. Like my wife said after getting rid of her 96 GMC SafariAWD Van" I will never spend another penny on GMCjunk" :(

[tophog]

Just some additional reading on vibration problems.

http://www.campingworld.com/forums/index.cfm/fuseaction/thread/tid/12982897/srt/pa/pging/1/page/1.cfm


http://www.sportruck.com/tech/archive/70866.html
http://www.automotiveforums.com/t141004.html
http://www.thecomplaintstation.com/g/_gm/00000342.htm
http://www.carsurvey.org/review_8514.html
http://www.agmlemon.freeservers.com/defectlick.htm

[atvpilot]

top hog,
just reading on of your attachements and one of the guys stated that he has a 2005 identical to mine and he replace the u-joint that connects his 2 piece drive shaft and it stopped vibrating. WHat do ya think????

[DmaxMaverick]

Try not to complicate things any more than necessary.

If it didn't do it before, and it does it now, something has changed (too obvious, huh?). A part, no matter how unlikely, has worn out, or broke.

The propeller shaft carrier bearing is a known weak link. Not just the bearing, but the insulator. Also, that single shaft is huge, and vulnerable. It wouldn't take much of a "ding" to get it singing.

Tophog. Don't rule out the tires, yet. They may be balanced, even load balanced. Possible you have tires that are out of round. I've heard of several situations that required numorous tire replacements due to this. One member here went through 5 or 6 replacements until he got a set of round tires. Different sizes and brands. Maybe he just had really bad luck. It could be that your truck is more sensitive to a specific condition than others?? I use only Bridgestone tires (on all my vehicles) and have never had issues with them, brand new to totally worn out.

Atvpilot
The mileage should be irrelevent. Was the vibration present before your warranty expired? I suggest you insist the dealer handle this appropriately. If not, check with other dealers. They have more descretion in these matters than they would lead you to believe. Look up the TSB. I don't think it is an "in warranty only" campaign. The weight in the bed thing has to go. It is no more than a band-aid, doesn't fix the problem, and creates an inconvenience for you.

[tophog]

"The propeller shaft carrier bearing is a known weak link. Not just the bearing, but the insulator. Also, that single shaft is huge, and vulnerable. It wouldn't take much of a "ding" to get it singing."

You're talking about the driveshaft correct? I had my driveline u-joints checked out at Six States here in Oregon. They put it on their balancer machine (not a lathe but something similar) and checked it for balance. They found .025" runout ...but no one seems to know what the spec is on the large, single-piece Spicer driveline ...however most agreed it wasn't enough to cause my vibration ... ?

I spent 2 hours last night out on the freeway driving back/forth between 2 exits just trying to brainstorm what it could be.

I came hope and jacked up the rear diff and placed the reardiff on jackstands. I then started the truck, put it in gear and let the rear tires spin at idle. I swear the darn wheels go up/down on both sides ...I took a straight edge and moved it in toward the wheel to verify roundness and do see the wheel is not spinning perfectly round. This was one of the first things the tire shop noticed and led them on the trail of replacing the tires/wheels with other sets ...which didn't change the vibration at all. I continue to think this is part of the problem ...but may not necessarily be the wheels?

Could there be something in the rear diff that is not right that would cause both sides to do this? If you looked at some of the pictures I have seepage out of the pinion ...but have read where this has been a problem in several other trucks and was the pinion seal. Just grasping at straws at this point.

I am getting my brother's OEM tires/wheels off his 2004 later this afternoon. At least I know his truck does not vibration so I'm assuming that will be a good test regarding tires/wheels.

[tophog]

Well I think I can take a deep breath after this evening ...and at the same time thank everyone for their very constructive and professional feedback.

I installed my brothers OEM tires/wheels this evening and there is no sign of a vibration. It felt like driving someone elses truck.

After reconsidering all the facts, what people said they had check on the truck (various combinations of tires/wheels, mounts, etc.) and also weighing the fact my truck drove very smooth for 14K miles until I swapped out tires and wheels I had a very strong urge to think the problem was related to the "what changed" question. Personally I found it very odd that something mechanical on my truck decided to break or otherwise induce a vibration with only 15K miles on the truck.

I went back to the Les Schwab this afternoon and went on another ride with the mgr that's been working on the problem since day one. I have to give Les Schwab credit as they have never tried to blow me off, send me elsewhere and have basically taken back 3 sets of new tires I had put several hundred miles on over the last few weeks. I'm sure they have worked on my truck more then any other vehicle in a long time.

We both felt the truck shake ...real bad at 45 mph and still bad around 60-65. We jacked it up again and ran it ...noting the vibration was there but not near as bad as going down the road. We could feel the vibration by putting our hand on the running board. I also stressed that I thought the rear wheels were going up/down (out of round) ...but I don't think he was as convinced that was the problem. In the end he told me he would be happy to put any tire/wheel combo on the truck if he knew it would solve the problem. With that I told him I was planning to install OEM wheels/tires tonight and would go from there. He commented they had already tried that with no luck. However he also indicated they only put the OEM wheels on the rear as they wouldn't fit on the truck due to the Ranch spindles. I told him that wasn't true and that Rancho actually advertises OEM tires/wheels would fit and come to find out he had a 265 or 285 tire mounted on OEM wheels which is why they wouldn't fit. The bulge of the tire hit the spindle.

I will be calling first thing tomorrow morning. At this point I definately know the problem are the non-hub centric Weld wheels. I need to find out if the 17" Weld Evo Renegades I had run before were hub centric or not ...if not, perhaps I just got lucky when they mounted them.

The delimia I have now is tires. If I stick to the OEM wheels my tire choices are very limited due to the Rancho lift/spindle clearance issue due the backspacing on the OEM wheels. I have been told by others that a 255-85R16 tire will work ...which would be fine as it would be close to a 33" tire and only about 10" wide which should fill out the fenderwells good enough to keep the truck from looking dorky. The OEM tires sure look like pizza cuttings on a lifted truck smile.gif

I guess I consider the book half-closed on my vibration issue since I am certain I have identified the problem but will feel better once I get a wheel/tire combo I like that doesn't cause problems.

I'll post again once have solved the problem once and for all. I'm open to wheel and tire recommendations if anyone has any. I know Dunlop makes a 255-85R16 as does BF Goodrich in the mud terrain ..which I like a lot (looks) but probably noisy and now mileage tire?

I want to thank DmaxMaverick for putting me back on the tire/wheel track ... ATVPilot ...sure hope you have some luck getting your vibration figured out.

Sorry so long ...

[More Power]

Random thoughts.....

My '01 CCSB4WD was included in the driveshaft bulletin, but it never exhibited the launch shudder others reported. Empty or loaded, it never shuddered on either an easy or hard launch. So, I did not have the 1-piece shaft installed.

I suspect minor differences in spring arch and/or pinion angles produced variations in this condition - ranging from none to bad. For what it's worth, some 88-98 C/K trucks with a 2-piece shaft also produced launch shudder to varying degrees, so GM has been aware of this phenomenon for some time - as has Dodge.

MP

[DmaxMaverick]

Tophog
Glad to see you a closer to a solution.

Just a note. The wheels on current SRW GM trucks are lug centric. The dually is hub centric. Still, don't rule out the wheels. They could be ovoid.

[tophog]

Originally posted by DmaxMaverick:
Tophog
Glad to see you a closer to a solution.

Just a note. The wheels on current SRW GM trucks are lug centric. The dually is hub centric. Still, don't rule out the wheels. They could be ovoid. Are you sure? We had to beat off the wheels off my brother's truck and could see where the hub of the wheel fit perfectly around my hubs. I was certain the OEM PYO (Alcoa) wheels were hub centric?

[DmaxMaverick]

The aluminum wheels have been known to stick to the hub due to galvanic corrosion. Search previous posts, some of them are quite extensive, and humorous at times. One guy actually drove around with the lugs loose for a rediculous amount of time, and they still didn't come off.

A hub centric wheel won't have conical nuts. My Centerline 16X8's are lug centric and I've never had a problem with them, or any Centerlines in the past. I have heard of several "off brand" wheels that don't work as well.

[atvpilot]

Glad to hear you might have solved your problem. I was told by my non gm mechanic that the area that connects the 2 drive shafts looks worn. So I am hoping that might be my problem. I have the stock wheels on my truck with the 265 BFG's.
pilot :confused:

[tophog]

I recieved email today from Alcoa stating the GM OEM PYO wheels are hub centric. They said the tapered lug holes are to help align the wheel with the hub as they are tighted.

After today you can set of glass of wine on the dash going down the hiway at any speed, vibration GONE. Fix: installed a new set of GM-centric aftermarket 16x8 wheels. Rides like glass now. Hooray!

[DmaxMaverick]

After today you can set of glass of wine on the dash going down the hiway at any speed You can do that in Oregon???
I thought stuff like that was only in Texas. They wouldn't use wine, though.

Great to hear you could do that theoretically.

[tophog]

Ok, a glass of Jack Daniels works better for me. smile.gif Off to work ...45 miles of "smooth" sailing. Dam%, what a releive this whole vibration thing is over. I am real curious to know what atvpilot's vibration feels like as well as others. I think my vibration due to the wheels was probably worse ...where after about 15 minutes in the truck you wanted to get out from becoming sick from the vibration. It was so bad it would have masked any other minor vibrations others may be describing. Nothing worse then vibrations ...heck, I'd rather have injectors go ...at least the diagnosis is relatively easy and fixed within a few days (once the dealer gets them).

[atvpilot]

top hog,
I have the stock rims on my truck. What did you put on the truck that I don't have? I am totally lost now. I am just going to park the damn thing and ride my motorcyle more. I haven't gotten any further than the last time we spoke. If you can email me a pic of the wheels at atvpilot2004@yahoo.com I would appreciate it. I am at my wits end and almost the bottom of my money barrel :(
pilot

[tophog]

atvpilot, the only thing changed on my truck during all this were the tires/wheels. I am confident the tires I "had" (Toyo Open Country A/T's) were fine however I used the opportunity to change back to BF KO's since the shop swapped me straight across for no out of pocket ...and I had 6K miles on them.

In my case, the Weld Outback wheels were causing my vibration problem for whatever reason. I personally think the wheels were defective (out of round). Also note, I have never run OEM wheels or stock tires which is the exact opposite of you. Our problems may seem related but the vibration source may be very different. Therefore I would be apprehensive in thinking wheels are the answer to your problem. I've never really heard of OEM wheels being bad.

The other big difference is I have the single-piece driveshaft and know there are issues with the 2-piece from reading TSB's.

I ended up with a 16x8 wheel with 5.25" backspacing. The wheels are Ultra Magnum Type 44's. You can see them on my truck here:

http://home.comcast.net/~tophog/duramax/2003_dmax.htm

So far so good. Have put 200 miles on them and no vibration.

[atvpilot]

Tophog,
Thanks for all the info.I did get your pic of the tire. I am gioing to my mechanic next week and have him look at the joint that connects the 2 pc drive shaft. When I had the shocks put on they noticed that thecarrier was worn. they said something about the rubber being worn???? I'll let you know what happens. Thanks again for all your input.
Pilot

[Turbo Al]

There are shops that have the capibility to shave the tire if it is out of round. I saw it done once and it was really slick. That shop has gone out of business but YOU would think a tire shop would know.
Also I would put the wheels without tires on the balance machine and check for run out.