I had a clunk as I acceled. It also occured when goin' into rev., and acceling in rev. I put all new u j's in, had the rear end updated (supposevily) , and it still does the same crap. Seems to be coming from somewhere after the transferr case. Any ideas?

 

Give us a little more information about your truck. Year, model, etc.

 

how full your gas tank is ? There is tsb it could be the bolt are loose on leaf spring and shacke torque tthem a gain the shaft spline with 4x4 need to be lube if the gas tank in not full the can cause the nosie to but they say it normal

 

It's probably the slip yoke. Take it out, grease it, should be good to go for a few months.