Finally, I found the source of the clunk...

the torsion bar crossmember bushings are bad...real bad

next saturday...

 

I have the same problem. Any idea where to get the new bushings?

 

from GM. i see this problem often.

 

Do you happen to know the part number?

 

i would have to have the parts guys look it up tomorrow.

 

THANK YOU for posting, I'll have to see if that is my problem....

 

I am wondering where these bushings are?

 

The bushings are in the torsion bar crossmember where it mounts to the frame.

 

part numbers?

 

It depends on which style you have.
If they look like dog bone things then this is the number. -15736950
Look here for pictures.
https://www.performancetrucks.net/fo...hlight=torsion



If they are the riveted on isolator then the number is -15153956
Here are some pics of that. This one comes with the entire bracket the old one has to be drilled out.