My issue is I can feel a clunk when I am driving. If I let off the gas, then give it gas I can feel a clunk. There is no clunk starting from a stop, only when I am moving.
The U joints all feel good and solid, and the back driveshaft makes a clunk going from reverse to drive to reverse.
Could it be a yolk issue? I have been reading about this dreaded GMC clunk issue but I don't know if that applies to my vehicle.
2005 Jimmy.

 

Sounded like my rear diff yoke when it went....

 

My understanding is there are 2 yokes on the back driveshaft. One that comes from the transfer case and the differential one. Is there a way to tell which one is the problem?

 

The back of the t case is a slip yoke. It's a splined shaft, that the driveshaft slips over. Then you got the u joint.

If the u joints are good, it's possible the slop could be in the tcase, or maybe in the diff itself.

On my '73 I was having a real bad clunk, and the car would roll quite a bit after being put in park. Turns out, the pin in the diff had elongated the hole in the carrier it went through, and was trying to cut the carrier in half lol

 

Just an after thought., If its NOT the universal joints,. I ran across one with bad cab mounts and it clunked like crazy. I replaced all joints, checked rear and front drivetrain components and still absolutely no joy, I replaced the cab mounts ( 110$) out of desperation and it solved the issue. The cab was sliding backwards on shifts and takeoff I'm guessing.and the clunk went away. directly afterwards. 1995 amd up s10s and s10 Blazers all eventually seem to have this cab mount rotting issue..I have replaced a lot of them throughout the years. It seems to solve a lot of problems, like replacing all the shocks and brakes AND ROTORS. iT'S CHEAP AND IT WORKS.

Just saying but more than likely its the u joints or the spline shaft (or yoke) where it all connects to the tranny.

The above referenced user is probably correct...

eGeekiel

 

Other: I had a clunk and was real dumb, new exhaust pipe not quite bent right and it made contact at frame past rear axle before it crossed over to outside. The slight shift in the pipe had it hit. Found it by mistake while repairing right rear brake caliper and bumped exhaust pipe and ohh..that noise is so familiar, I wonder.... yep. Took a heavy long bar and some wood and bent it a bit the other way, noise gone.