ZF issues

[amcgibbon]

Gentlemen,

I need your input. I took delivery of a 2003 GMC Dura/ZF crew long 4x4. This is the 3rd ZF I have owned and is a test order for a group of 30 trucks to be ordered in the next two months for our companies. I have what seems to be the same issues as others have complained about.. A creaking clutch as well as the "bucket of marbles" random noises coming from the tranny area. The ZF shifts nicely and have had no problems as of yet. But I am seriously thinking about not placing our big order for any GM product. (dont even think about selling me an allison) Has anyone solved any of these problems lately? I have not noticed any final solutions to these common issues with the clutch. I would appreciate any input as this could result in us changing our fleet account to Dodge. Lets see if we can avoid that.

[Landscaper]

I've heard that some have found a fix for their squeaky clutch, I haven't looked at mine yet(been to busy). However I can say that the bucket of marbles feeling will go away after 3-5k. It just takes a little while to break it in. I currently have 15k on my truck 85% with 4-10,000# worth of trailer behind it. I still love that 6spd. :D

[ 01-20-2003: Message edited by: Landscaper ]</p>

[C J Fairall]

amcgibbon
I have experienced the same symptoms with my truck. At about 5500 miles I deveoped the squeek when depressing the clutch. I got irritated and tk off the small overcenter spring , complete with plastic attachments, located at he top of the clutch pedal. I now have 43000 miles and no apperent problems.
As for the bucket of marbles sound, I too experienced that at approx. 25000 miles. This sound was most noticeable during declutching while decelerating. The problem, bad dual mass flywheel. It seems that the cusion springs between the 2 sections of the dual mass flywheel collapsed, causing uncontrolled movement between the two sections. I just recently replaced a dual mass flywheel in another duramax for the same noise and found the same condition. My truck is an 01 and the other truck ws an 02. Now my truck is starting to make the same noise again (not near as loud)at 43000 miles. I am going to talk to the district service manager next thursday and try to get some insight as to what is going on. Are they upgrading the flywheel or are they replacing them with the same week part. BTW I have heard of others with the same porblem.
Good luck hope this info helps.
Jim.

[srubrn]

amcgibbon,

Can't tell you much about the flywheel issue, but I can tell you in the 2002 models, all three of the truck manu. were using the ZF. Also you might want to think about switching brands right now. Both the other guys have new diesels they have not proved themselves yet. The Cummins has the same Bosch fuel injection that our trucks have and they have not had that combo before.

[DmaxCC6spd]

Amcgibbon, I agree with C J Fairall about the overcenter spring. I got rid of mine for a popping in the clutch pedal and haven't had any problems. I only have 15K on my '01 truck, but I love the ZF. It does take some time to break in, but once it wears a little and since I removed the spring, it shifts like a sports car.

Can't speak about the clutch since I have no had any problems with it. I don't tow ofter and when I do its under 6000lbs. I have managed to get rubber on the 2-3 shift as labeled on the shifter. So far so good.

[GMCTRUCK]

I haven't had any noises coming from my ZF box. For some reason the clutch pedal does squeak during warmer weather. It won't do it cold but, even in the winter once I've been on the road for awhile and the floor heat has been going long enough to get real warm down there it will start to sqeak. Although it doesn't get loud enough to drive me nuts. Shifting was really tight and notchy new but, its getting better with mileage. It will consistantly bark 4th with 265s. As far as switching to Ford check out www.thedieselstop.com and click the 6.0 Powerstroke section. They are having tons of problems and many different types of problems with the new engine. As far as the Dodge the Cummins with 6 speed and the axles should be fine. Just don't forget the rest of the truck is made by Dodge.

[ 01-21-2003: Message edited by: GMCTRUCK ]</p>

[DeepVee]

I had some of the same problems. My squeaky pedal was replaced when the pedal started popping.

My biggest problem now is a chatter noise through the shifter in 4th, 5th & 6th when accelerating or going up hill. The chatter has been getting progressively worse and is now starting to do it on flat land.

2001 with 22,000 miles

[ 01-21-2003: Message edited by: DeepVee ]</p>

[amcgibbon]

I appreciate all of the input. I certainly do like this truck quite a bit. It is comfortable, capable and economical. That clutch is the only weak link that I have found and I drive the heck out of trucks. I have originally had dodges and they have the best engine out there, but the the truck around it is a junk heap and the new ones look like pregnant goldfish. Please do keep me informed if any of you with the ZF find a fix for the clutch issue that GM will take care of (flywheel problem too Mr. Fairall). I would appreciate any input and advice. email me anyime. AMCGIBBON@AOL.COM

[CPMac632]

DeepVee sounds like you need a new flywheel.

[DieselDennis]

SruBurn,

While GM and Ford both use a ZF6 manual tranny, Dodge uses a New Venture 5600 for their manual work. Ford has been using this same transmission since 99. I have personal experience with a 2000 F350 ZF6 with 50,000 miles and no trouble. I assume that the Ford clutch and the GM clutch would be the same?

And FYI Dodge now has an automatic to go behind that H.O. Cummins.

[CPMac632]

Diesel Dennis I have seen the clutch and flywheels out of GM's and Ford's and they are not even close to the same.

[Jelisfc]

I've got 7500 miles on mine. The clutch pedal creaks but the stereo cures that. It's plastic and I don't believe the creak will ever go away unless it's a steel pedal. I haven't looked but my clutch pedal pressure is great so if they still put the overcenter spring on '03's it's not enough to notice. I get a little banging in the drive train when empty and I push in the clutch coming into a driveway. I think it's the torque in the drive shaft bouncing back and forth. The clutch pedal gets hard after continuous highway driving and when I do stop the trans howls like the lube is too thin. I don't care about the noise I just hope if something is wrong it blows up before 36K smile.gif Having said all that I'm glad it's a stick...even though I have caught my self pulling the shifter out of 6th looking for 7th. Now that would make it perfect.

[crafty]

I'm not sure what I'm doing differently but after 44,000 kms and two years driving I've not had even a peep of a squeek from the clutch. I love the trans. It is stiff to shift in this real cold weather but then so was the one in my old 6.2 truck. I sure wouldn't go as far as to not buy a GM because of the clutch, but then that is just my opinion. :D :D :D
P.S. Glad to see that I'm not the only one who has tried to shift into 7th Gear!!!!

[ 01-23-2003: Message edited by: crafty ]</p>

[amcgibbon]

I agree with you.. I would not stop buying a GM truck just because of the squeaking clutch. My concerns lie mostly in the flywheel. I certainly would hope that an aftermarket company would come out with a quality replacement and that would ease my concerns. I have never had a problem with the ZF per se and I love about 99% of the trucks overall fit and finish and content. The clutch only squeaks when it is 60F or above. The only problem is that I live on the Mexican border and our winter time temps are around 65F in the daytime. I guess that is the price we pay not to have to deal with that snow. :D

[Colorado Kid]

These post have me a bit nervous, but I still love my truck. My clutch pedal only squeaks when it is REALLY hot (90*F+ outside, sitting in the sun all afternoon) in the truck. Other than that nocomplaints except the early "sticky" shifting, which wore off buy about 10,000 miles. That and I'd like a second reverse at around 12-15:1 and a seventh gear at 0.60:1. My '91 has 3.08 rear and the D-max with 3.73 is just too responsive on the highway ;) . With 0.60:1 top gear 2000 RPM would be 85 MPH...purrrrrrfect for an unladen D-max.

Pulling the 5th wheel the gearing is great, but unloaded I've pulled the shifter out of 6th to upshift a lot more than once!

The flywheel replacements (if necessary) will be covered under warranty until 5 years/100,000 miles (I checked, it IS mentioned in the "included" list in the engine warranty) After that the $2300 I didn't spend for the Allison should cover it at least twice...by then somebody should have figured out something that works. The fixes exist for both manual and auto trannys from the competeing brands, and for the Allison in high power applications...the problem is that there are far less D-max/6 speeds than any other Diesel/Transmission pairing in pickups.

[DeepVee]

I don't think my noise is the flywheel, but I plan on taking it in to get checked sometime soon.

Also, did anyone with a ZF Crew Cab or Long Bed ever get the one-piece driveshaft?

[CPMac632]

It might not be DeepVee I have been wrong lots of times before but that is exactly the way my second flywheel sounded before it broke completely in half.

[Jelisfc]

Colorado Kid, I think a light duty nine speed would fit the bill perfect. You could split reverse too.

[DieselsRule]

Jelisfc
Take the truck back in and have them put a new slave cylinder in it. I had the same problem with my clutch getting real hard to depress when it was above 80 outside and after driving on the highway for 45 minutes or so. If you check your slave cylinder, fluid is probabaly jet black. They tried 1st,Flush fluid, 2nd Wrap line with heat tape, and then 3rd, the correct way replaced the slave cylinder and pressure plate. It's been fine ever since.

I chose not to get the Allison BECAUSE GM got involved with it. After replacing 4 4L60's on two of my other trucks, I did not want to go the Auto route again.

I love the 6spd and when empty usually look for at least one more gear to cruise. The only thing I don't like about it is Reverse is geared way to low. As far as mpg it's been 20-21 mpg since New except lately 17-18 on this winter fuel crap.

[DieselsRule]

Jelisfc
Take the truck back in and have them put a new slave cylinder in it. I had the same problem with my clutch getting real hard to depress when it was above 80 outside and after driving on the highway for 45 minutes or so. If you check your slave cylinder, fluid is probabaly jet black. They tried 1st,Flush fluid, 2nd Wrap line with heat tape, and then 3rd, the correct way replaced the slave cylinder and pressure plate. It's been fine ever since.

I chose not to get the Allison BECAUSE GM got involved with it. After replacing 4 4L60's on two of my other trucks, I did not want to go the Auto route again.

I love the 6spd and when empty usually look for at least one more gear to cruise. The only thing I don't like about it is Reverse is geared way to low. As far as mpg it's been 20-21 mpg since New except lately 17-18 on this winter fuel crap.

[C J Fairall]

Gentemen;
I have some additional anformation on the dual mass flywheel. First there was a part number change in march 2001. My truck was produced just prior to march 01 and have since changed the flywheel. I am also assuming that most of those who have posted to this thread, have trucks produced after march 01. Therefore all have same part??
I did talk to the district service manager about this flywheel situation and he was unaware of any "service issues". The factory did call for a return of the last dual mass flywheel that I changed, guess that they want to examine it. The district service manager said that was a good sign.
If I recieve any additional info. I will pass it along.
Jim.

[srubrn]

Deiselrule,

I find my reverse is geared way too high. I have to put my truck in 4low to get it to back my camper up, uphill without shuttering,actually bucking, the whole truck bucks. I changed the way I let off the clutch and it still does it. I put it in 4low and it will do it fine. I was wondering what two wheel drive people do!!

[DeepVee]

CPMac632,
Thanks for the info, you may be right. I've been hoping someone has had the same symptoms and found a fix. Just wondering why mine does not make any noise while engaging/disengaging the clutch, just the chatter when loading up the drivetrain in 4,5 & 6.

I'll let the dealer figure it out and let you know.

[CPMac632]

The first flywheel in my truck made rattling noises at partial depression of the pedal. My second flywheel made no noise at all while depressing but rattled or grumbled while accelerating in the higher gears and when I took it out it was in two pieces the first one was just loose when it was taken out.

[1BADDMAX]

My truck was built at the end of April 2001. There have been no strange noises other than the couple of times when I have been in a low gear and pushed the clutch in way too fast (nice clanking, clunking sound). The truck now has 45,500 miles. It would be interesting to see if the trucks that had most of the flywheel problems were made before the part number changed. So far so good, Knock on wood.

[luvthesmellofdiesel]

I have the '02 4x4 crewcab ZF-6 and I can tell ya'll one thing, I am sure glad I didn't get the Ally from all the problems I have read about, besides, you can't beat a standard. I used to have a 465 4spd in my '91 GMC 1/2 ton, I am convinced the ZF-6 beats that combo for low-end.

The only issue I have is, I think we need a 3.43 axle ratio. In 6th, I shouldn't be spinning 2500rpm's @ 85mph, it should be more like 2200rpm. I suspect GM won't offer the 3.43's in this weight class cause the Ally wouldn't do well with it, and certainly no gassers would use it, so it's only the 6600 w/ ZF-6 and do it's probably not worth it to GM. :-( We could actually use first gear for something if we had 3.43's... :)

Anyone know what kind of torque the ZF-6 will handle (and the clutch) when it comes to adding the after-market power boxes? When my warranty is up, I would like to buy one. It sounds like the Ally is at its limits stock.

Thanks,
Tim White

[DeepVee]

I took my truck into the dealer yesterday. The foreman and I went for a ride on the freeway so I could demonstrate the chatter. The truck was empty so I explaining that it's a lot worse when the truck is loaded or pulling a trailer. He went out later with his shop manager and they came to the conclusion that the chatter is normal gear noise. I disagree but he did sate that if I want to bring it back in with a load they'd be willing to look at it again. I'll also give it some time and see if it continues to get worse, which I'm sure it will.

CPMac632, Did you have your service done at a GM dealer? If so I may ask you for the name so I can and ask my dealer to contact yours about the noise. The shop foreman here didn't even think GM was using a dual-mass flywheel with the ZF.

DeepVee
firstvee@yahoo.com

[ 01-29-2003: Message edited by: DeepVee ]</p>

[CPMac632]

My first flywheel was done at the dealer but they are not very good for reference and the next one will get finished at the dealer but it isn't yet. The service writers can quickly find out about the DMFW problems if they want to. And I believe the reason that dual mass flywheels are in our trucks ZF requires them in front of all their transmission to reduce gear noise not for the diesel engine. I know I'm going to catch it for that statement but explain why the 8.1 and the corvette has a dual mass flywheel. But since that is the purpose of the flywheel, to eliminate gear noise then they should have to replace your flywheel if it is getting worse.

[Colorado Kid]

When our trucks were new the 6 speeds torque limit was 540 lbs-ft. Apparently it has been uprated some since then, as the G2 PSD makes more torque than that. One very imprortant effect of a dual mass flywheel, which might be why ZF requires them, is the limiting of peak input torque. When some limiting torque is exceeded the friction ring on the DMFW slips, protecting the transmission. If you put a lot of weight on the back of your truck, rev it up to say 2500 RPM and dump the clutch in second...like if you were trying to win a hill climbing contest pulling a trailer... ;) ...it'll slip like crazy, and won't stop slipping until you back all the way out of the throttle. I thought it was the clutch at the time, but am now convinced that it was more likely the DMFW. Unless a "tighter" DMFW is used I'd say that we are already right at the limit in stock condition...the stock configuration can slip the DMFW friction ring, although you have to play rough to make it happen.

I'm still hoping for the aftermarket to solve this problem for us...hopefully before I have a failure after 100,000 miles. :rolleyes:

[DeepVee]

After doing some research I'd have say I agree with CPMac632, one of the reasons the DMF is there is to reduce gear noise through the trans.

Sounds to my as though my DMF is not dampening the torque peaks when I load up the engine and is transmitting noise into the transmission gearing.

I have to take the truck back in next week for a new steering shaft and plan to push for a new flywheel.

[ 01-29-2003: Message edited by: DeepVee ]</p>

[CPMac632]

I don't know about your dmfw but I know mine has NO friction ring and could not slip internally until I broke it in two. But I have heard others mention the friction ring also but it does not exist in the flywheels I have seen with the exception of the powerstroke flywheels because I simply didn't pay attention to those so I don't know.