weird clunking/thump noise from rear-end

[cockblocker]

Hi All!, Ok I've got a 99 Tahoe that I bought after being repaired from a front passenger-side impact. I have the original invoices for the repair which they only replaced the inner/outer fender, front bumper and fan shroud. But I noticed from the get go that when I come to a complete stop, then release the brake I get a sound and a feeling like a u-joint is going out. It only happens from a complete dead stop and only in forward gears. I have tried coasting, then gunning it and didnt feel a thing. I also tried coming to a stop, switching to neutral, then back to drive, release the brake and the noise/feeling doesnt happen...very weird. So then I got underneath while it was in Neutral and the wheels chocked, twisted and shook the driveline. It has about a half inch of play in the rear-end, and both u-joints appear solid. The guy I bought this from told me that sometimes when a wrekced vehicle is towed they will remove the driveline...Has anyone else ever heard that? He also said that if that happened that maybe they didnt torque everyhting down enough and that some type of binding might be causeing the noise. He did say that he would pay for any repairs...the only problem is that I am in MS and he's in TX..plus I have two kids and can't be without a vehicle unless absolutely nessesary. Any help? Anyone else seen this before?


Thanks!!!!!

Ben

(sorry it was so long)

[PETHO]

I had the same problem with my 99 tahoe. Change your Transfer case oil. Need to get GM's New oil, blue in color. Drain oil and add in new. Paid about $8.00 per quart, bought three , but only used 2, also needed is a hose attached to the end of the quart bottle ,because of tight area to add oil. Fix my truck , clunk when away with in a day and never can back.

[cockblocker]

I guess it would have been helpful if I had said that mine is a 2wd...not 4. Well after some intensive searching through pretty old posts I found a TSB 01-04-17-004 sating a new nickel-plated slip yoke was a supposed "permenant" fix. But after calling a GM dealer here in Vicksburg I was told that even that isnt a fix...but it will last until roughly 20k miles..then the clunking will come back. Somehting about an ungreased yoke from the factory causing the slip yoke not to slip.

[typicalsituations]

I have heard that the Blue fluid will help. I just feel like if it wasnt made for our cars, then it should go in it. I can live with my BUMP, but I think its getting worse.

[cockblocker]

well after discussing this more with a local dealer, the shop guy indicated that for my VIN they didnt make a nickel plated yoke. So I guess Im going in for a lube job.

[aero246]

as posted by typicalsituations "I have heard that the Blue fluid will help. I just feel like if it wasnt made for our cars, then it should go in it. I can live with my BUMP, but I think its getting worse."

Just so you know that blue fluid was made just for the Transfer-Case. It is used in the GM Transfer-Cases now "factory fill" as the old fluid was not working well and they were having troubles with broken cases. This I beleive is a synthetic fluid.

[typicalsituations]

See I've heard alot of differerent things about that fluid. That last thread I read about that fluid said that it was made for some auto traction tranfer cases, and wasnt meant for tranfsfer cases that weren't that kind. I guess I'll have to ask the dealer... I would love to fix that bump.

[RexNfx400]

Go after the rear leaf springs. Sometimes this is called "driveline stop clunk" or "bump/clunk upon excelleration"
Just annoying, not damaging. Thats is, if this is the same problem.


There is teflon grease for yokes also.

Blue lube is for NP-246 automatic T-case only