drivetrain clunk

I have had a drivetrain clunk in my stock XJ for some time. When i am driving down the road and let off the gas there is a clunk,almost like a slip yoke that is not lubed. I thought this was the problem so i had it at work one day on the lift and removed the driveshaft and lubed the yoke up. Installed new ujoints and reassembled.Still there??? Anyone have this problem?
Thanks in advance.
Specs on XJ
96 Country Edition
4.0,automatic,4wd.

I had the same but now it went away once I installed an RE 2" BB.

I have that exact same thing on my 90. I've wondered what it is but never been extremely worried about it, because mine has done it for 5 or 6 years now. It actually used to jerk back very bad when you let off the gas now it just clunks though.

I am concerned if i do not resolve the problem , it will only lead to problems in the transfer case or rear end..

Same thing in my 99. The easier I let off the gas, the lighter the clunk. But if I have to stop in a hurry, and let off the gas quick, especially under heavy acceleration in 4th gear, the clunk is very noticeable. Like when exiting a highway, or something.