drivetrain or Trans?

[00mike]

I have a 98Yukon, 5.7, 4x4, love it and all 122k miles I've put on it.
But, I've finally got a problem I can't decifer on it... after I've come to a full stop and accelerate, I get a clunk I can hear and feel.

It's almost like the rear axle is pulling back or there is an inch of play in the drivetrain that jolts or goes in and out like an accordian when I stop and go, though there is no clung on the stop just the acceleration...

I was thinking it could be a transmission though I don't sense any problems of gears shifting...and I don't want to spend more on a transmision than the car is now worth...
Anybody have any thoughts?

[tonytone]

Assuming that your tranny is fine otherwise, I believe there is a TSB for the exact symptom you're describing; IIRC it's something to do with the yoke, and that the "band-aid" solution is to regrease it or something like that. I'm sure the GM tech members on this board will come by and clarify what I just said, but I'd look into that, for starters.

[00mike]

Thanks for the tip!
Did a little more digging per your response, and I did stumble upon a TSB blurb on some odd web site:
Rear End / U-Joint
Upon acceleration, braking, or hitting a bump a loud thump or clunk is heard coming from the rear suspension. It is caused by a lack of greas in the sliding yolk on the driveshaft and a defective disign in the u-joint. Dealers are re-lubing the splines on the yolk and iserting a rubber ball in the u-joint.

I haven't gotten to test this solution out yet but will ASAP. If anybody is interested I'll report back.
Thanks again!

Originally Posted by tonytone

Assuming that your tranny is fine otherwise, I believe there is a TSB for the exact symptom you're describing; IIRC it's something to do with the yoke, and that the "band-aid" solution is to regrease it or something like that. I'm sure the GM tech members on this board will come by and clarify what I just said, but I'd look into that, for starters.

[carrolmcc]

I had the same problem with my 2001 4WD (61,000 miles). My mechanic told me it was the spider gear in my rear differential. Upon inspection, he found bits of the gear inside the housing. My extended warranty provider (which I'll be happy to name if anyone is interested!!!!) will authorize the repair, but only with a used part from an auto dismantler who claims that there is 50,000 miles on the used part.

The inspector (for the warranty company) said that this is a somewhat common problem in trucks with a posi-traction rear-end. And it usually happens between 60K and 100K, so make sure that you don't have the same problem.

Further, the warranty company will not provide any written documention to me -- "verbal only." Has anyone else had this experience with warranty companies?

[Chevy_girl00]

My boyfriend had a clunking and jolting when stopping or accelerating and after about a week his gears started to go out. Took it in after inspecting and reinspecting himself and finding nothing wrong. Turned out he had a crack in his transmission, had to pay $3000 to replace it. Maybe you should check out your tranny just to be safe.

[Chevy_girl00]

Actually check out this thread too, might be of some help: http://www.automotiveforums.com/vbul...d.php?t=202832