Horrible driveline vibration... help

[1919a4]

I have a CA-emissions 02 D/A SB CC LT and have been running Juice level 1 most of the time.

I've been juiced for about 4 months. Anyhow, I towed a large trailer weighing about 12000 pounds (hitch mount) a few weeks ago. I used Juice level 2 and have an Isspro EGT and boost gauge. I noticed while accelerating, at anything over 1/2 throttle, the 1-2 shift was accompanied by a very violent high frequency shudder. There was no hint of wheelspin or wheel hop.

I just moderated the throttle, and thought to myself this must be the dreaded "fishbite" that juicers talk about.

It was pretty bad during the trip, so after getting home, I pulled off the Juice to see how the vibration improved.

It didn't. Even without juice, the 2nd gear shift (or even second gear, full acceleration) will shake the cab violently. I have a limited slip diff.
Trans levels are OK.

I'm headed to the dealer unless you guys can figure this out.

SImon

[mdrag]

1919a4,

Welcome to TDP forums. Take a look under your truck and see if you have a 1 or 2 piece drive shaft. The one piece is HUGE, so you should be able to tell easily.

There was a TSB on Launch shudder on acceleration, where the 2 piece drive shaft is replaced with the 1 piece. I don't have acces to my notes right now to see if your truck's configuration qualified for that replacement.

Try a search using driveshaft, drive shaft, or launch shudder in the 2500HD/3500 HD Trucks and Drivetrain forum and I think you will find many posts.

I'm moving this topic to the 2500HD/3500 HD Trucks and Drivetrain forum.

[mdrag]

1919a4,

Here is the TSB info posted by 77TransAm, and it appears that you would qualify for the 1 piece drive shaft with a CC shortbox:

http://forum.62-65-dieselpage.com/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=7&t=003136&p=

One word of caution - if you need to have this done, MAKE SURE THE DEALERSHIP DOES NOT CUT OUT THE CROSS MEMBER!!! It has happened to others. Only the center bering support bracket needs to be removed, not the entire cross member.

================================================== ========================================

Launch Shudder on Acceleration (Install New One-Piece Propeller Shaft) #01-04-17-001B
1999-2002 Chevrolet and GMC K2500/3500 Extended Cab Long Box and Crew Cab Short Box Pickup Models With Automatic Transmission

This bulletin is being revised to add model information, remove procedure steps and change parts information. Please discard Corporate Bulletin Number 01-04-17-001A (Section 04 -- Driveline Axle).

Condition
Some customers may comment on a vibration during acceleration from 0-40 km/h (0-25 mph). This may also be referred to as launch shudder. This condition may be more noticeable when the vehicle is carrying cargo or is used for towing.

Correction
A new propeller shaft is available for service to correct this condition. This new propeller shaft is a one-piece design and will replace the current two-piece design.

Install a new one-piece propeller shaft on affected vehicles. Refer to the service procedure and the parts information listed below. Match the affected vehicle with the appropriate propeller shaft. Refer to the usage information below. This fix does not apply to the Chassis/Crew Cab Models (K35943).

1.Remove the propeller shaft assembly and the center bearing. Refer to the Propeller Shaft - Two Piece procedure in the Propeller Shaft sub-section of SI2000. For this bulletin, it is not necessary to mark the components for re-assembly.

Important
The center bearing support bracket (1) must be removed in order to provide enough clearance for installation of the one-piece propeller shaft. Avoid damaging the crossmember during removal of the center bracket. For proper clearance, no more than 13 mm (

[1919a4]

No, I have the large aluminum Spicer one-piece shaft.

This isn't a vibration; it's a cab-shaking earthquake that feels like the transmission is gonna jump out of the truck.

SImon

[deerhunter7]

Sounds like a loose torque converter or cracked fly wheel. I would go straight to the Dealer..
Also check to make sure your drive shaft u bolts
are not loose or broke..

[ 09-05-2002: Message edited by: deerhunter7 ]</p>

[glamisboy]

I'm glad (sort of, sorry) to hear someone else has what I've been experiencing. The dealer claims there is nothing wrong, as they always do.

Two days ago was the first time I felt crash/clunk/jerk while empty, jumped in truck & started it up, let 'er warm up as usual. Slowly crept to exit the parking lot, as I climbed up a slight incline the whole darn truck slammed/crashed/clunked/jerked. I slammed on the brakes, thought what the h@@@ was that. Luckily my buddy put my concerns to rest when he cheerfully reminded me what dealer said, "Oh there's nothing wrong".

Oh, ok that's normal too right ???? I'm not sure if I have a 1 or 2 piece shaft, but I do know I have a longbed crew. Anybody have any ideas ??

[TLA]

You should have a 2 piece shaft. I don't think there is a one piece for your truck. I recall that there have been problems with the slip jount lube, and that there is a new lube available (a warranty item). Also, there is a nickle plated slip joint yoke for it. I'll try to find the site for TSB's. Try a search for slip joints.

[Red Diesel]

I have a 2002 CC SB 2WD with a 6-speed and ever since the day I got it, if I go over a bump or the truck jumps from letting the clutch out too fast I hear a clanging noise underneath. It is especially noticeable when I back up my inclined driveway and push the clutch in fast and the truck stops. Could the 2-piece drive shaft be causing this. The dealer said it is normal and that it has to do with the HD suspension. Any thoughts or especially any fixes????

Thanks,
Nick

[nukedmax]

1919a4 Who is your dealer?

[NutNbutGMC]

^...Red Diesel, dealer, service rep or whomever is feeding you that line is full of BS, plain and simple. What an insult to your intelligence. There is a root cause and a fix. I'd like to help you but there is too much mixed info here and not enough specific to your machine.

[1919a4]

email me and I'll tell ya who the dealer is; they've been very accomodating and professional.

BTW, see the new topic- "Allison is trashed."

The Allison failed the stall test and self-destructed. A new one is on the way and I'll try to get details on what let go.

-S

[nukedmax]

1919a4 Hate to admit this but can't figure out how to email you.

[1919a4]

email me at:

SCIMGXXX@earthlink.net

(remove the XXX to get to me)