Rear end drop when accelerating

[Zanter22]

Hey everyone. I own a 1996 Chevy 2 door Tahoe 4x4, 3.73 gears, g80 and 285/75r16 on stock wheels.

About a month ago I noticed a bit of a clunk coming from the rear end when accelerating from a stop. It also seems to drop a bit with the clunk.

So my question is, does any of you guys have an idea what this could be? Could it be a problem with the e-brake not properly releasing? Cause my e-brake pedal does not spring back, I have to pull it. Let me know what you think.

Thanks

 

[SkyHighColorado]

U joint maybe.

 

[Zanter22]

Yeah maybe, I just don't know why it drops down.

 

[vortecv8~5.3l]

They rotate due to tork. Rotation is normal. Define dropping. Pinion angle is actually set a little high to keep from binding/breaking u joints under heavy acceleration. Define clunk.

 

[98_k1500]

I have seen several of these trucks with auto transmissions do this. When you start from a stop (red lights especially) you feel a driveline clunk and it feels like the rear of the vehicle drops about 1/2" at the same time. I have never dug into one to see why it does it, differential cross shaft wear would be my prime suspect. May want to set the park brake, put the truck in neutral, and see how much you can turn your driveshaft. A little play is normal but if it turns alot before loading the gear either way, your cross shaft is probably heavily worn. If you have a locker, I feel for you, because those parts are not easily available.

 

[Zanter22]

Alright thanks for the info I'll get my e-brake set abd I'll see if there's any play in the driveshaft. If my diff is on its way out would it be better just to swap in a 14 bolt or fix the 10 bolt?

 

[98_k1500]

Honestly, I wouldn worry about it unless the clunk gets violent or something. I have seen many of these go no telling how many miles like that without any ill effects.

 

[Zanter22]

Thanks for the info. I'll just see if it gets any worse and maybe check the diff fluid.

 

[BoxerPitMix]

This may be interesting for Tahoe/Yukon owners.

http://www.tahoeyukonforum.com/forum/showthread.php?t=38275


There is apparently a nickel plated slip yoke that eliminates this on these trucks. Why it doesn't do it on pickups - I have no idea... But after doing a lot of reading through TahoeYukonForum.com I've seen where many people have addressed this.
What you may try doing is pulling the drive shaft, grease the inside of the yoke and put it back on - see if that eliminates the problem. Not a permanent fix but it may at least help you figure out where the noise is coming from. I know I've read somewhere also that someone drilled a small hole and put a zerk fitting on the yoke and greased it from time to time to eliminate the problem...
Mine does the exact same thing and it drives me nuts.

 

[94Sierra4x4]

Mine does the same thing, carrier in the rear end is worn out where the cross shaft is located, i believe.. like 98 k1500 suspects. but not 100% sure why it drops down like that. Worth having a look inside the rear