ok.. I'm at a loss now.. here's the story... I bought my truck a few years ago '88 C1500 350 TBI... it had like a clunk to it when you'd let off the brakes after a stop .. or sometimes it wouldn't do it t'ill you went to accelerate.. it turned out to be a broken tranny mount.. ok so that was replaced and the problem was gone.. a few weeks later it starts doing it again.. also at some point the ujoints where replaced.. I don't recall when I had that done though.. then the bottom end goes in the engine .. as some of you know... so now I have my nice fresh engine in along with new tranny mount again(because I bought the energy suspension engine/tranny mount kit).. everything is nice and tight on the tranny.. but I still get that dam kick when I let off the brakes.. I noticed if I stop hard and the truck kicks back when I stop it won't do it when I let off the brakes.. also if I stop and while holding the brakes I put it in newtral it will make that kick sound /feeling.. you actual feel it.. really seems like a driveline thing.. if I go from reverse to drive I don't get a big clunk like you would when a u joint was worn.. I know the u joints I have aren't greasable because they are gm replacments.. is there anyway of checking the u joints visually??? or anyone have an idea wheather it is a bad u joint??

thanks

 

grab ahold of the driveshaft, try to rotate it, and see if it has any play in it at all. it shouldnt have any at either end.

 

k.. I'll check that tomorrow nite.. I thought there was suppose to be some play.. between the tranny, the ujoints, the gears in the rear..

 

OK it seems that you have a VERY common problem,I have the same one on my 92 c1500 excab.It looks like you have a standard cab and if it is not your u-joints,try installing urethane bumpers on the overload spring in place of the anti squeak discs.This will hold the axle from windeing up and binding the drive shaft when you stop. Vary the thickness of the bushings untill you find a comfortable medium. Hope this helps
Jaymz

 

hmm.. ok.. if I lift up and down and the rear end I can't seem to get it to do it though.. these bumpers something you get at a spring shop?

 

The axel only seems to wind when you are braking,this is a hard thing to simulate. If you see the holes that removing the plastic dics exposes this is whare you install the bumpers.I used energy suspension traction bar bumpers that I cut down.What you are doing is increasing the spring rate and locating the axel better.