Naturally, I assume it's the U-joints. With the truck off, I crawled under, didn't see any play, tried to jiggle the driveshaft, and it would not budge. Still the U-joints, or is there something in the transfer case that could do this as well?


1993 GMC Sierra K1500, 118,000 miles.

 

Mine did the same thing and couldn't confirm the extra play in it. So I took it apart and it was the back u joint that connects the driveshaft to the rear end. It pretty much fell apart when I took it down. Easy to change out. Just need a torch to heat up the nylon inside the pin holes. Just heat up till it squirts out. Then install new ones with c clip.

 

My brother had a tahoe that was doing that and it ended up being a rear shock that wasn't tight enough on the lower mount.

 

Shocks are tight, no problem there.



I should fix the U-joints in the driveshaft of my old truck, but I'm selling it. Not only can you see literal gaps in the U-joint spaces where the driveshaft connects to the rear end, but you can also slide the driveshaft up/down/side to side. It's real bad.


I'll probably just replace the U-joints anyway. 120K, it's about time.