Ok Ok, I know this technically is not a S-10 but very close, 1996 Oldsmobile Bravada with the AWD T-case. It is clunking(feels like chain slipping is best as I can discibe it) under acceleration from a dead stop or under load. I have checked all the shafts and seem fine, I have it narrowed down to I believe the T-case, I have alot of play out of the rear output shaft.

First question: Any idea's of what it could be or point me in the right direction?

Second: If I need to change out the T-case, will on from a 1990 Astro Van with the AWD system work in it?

Third: What other choices do I have?

Thank you very much for your time in this

 

I would start out by checking your transfer case mounts to see if there is a problem there. Also check the u-joints in the driveshaft since you mention play in the driveshaft (or were you referring to just the output from the transfer case?).

Another source of this sound could be the torsion bar cross member. There is an isolator mount on the passenger side IIRC which if bad, can cause a clunking noise when under acceleration.

I am not sure if the transfer case from the 90 Astro would be compatible with your truck. There have been a lot of changes since then in the transmission and I cannot remember when they made the change from a square 4 bolt pattern to a hexagonal 6 bolt pattern at the back of the transmission.

 

The play I was talking about is in the actual output shaft, I thought U-joints at first but they are solid. The sound is not just one thump or clunk, it is more like a constant clunking sound till I let off the gas. You know like clunk clunk clunk ETC till I let off, but alot faster then that,,haha. It honestly at first thought sounded like a transfer case chain slipping sound. I have had that happen in older 4x4's.

Any other idea's and how can I tell if the T-case out of the Astro would work?

 

Start by seeing if it has the same bolt pattern at the front. Electrical connections would be next.

Have you pulled the driveshaft and inspected the slip yoke. I have seen a few of these crack and lead to excessive play. Could also be the bearings on the output shaft.

 

Could that be the cause of the sound I am hearing? I would much rather fix this T-case instead of putting another one in if I can. Is there anything else that would cause this sound? I know hard to say with out actually hearing it yourself.