Can someone give me some insite as to what might be causing my rear dif to make a light thump when I accelerate off the line? I don't mean stomp on the gas either, I mean just starting it will make a thumping feeling. Just once, not while driving. I do know that I need to rebuild my traclok but I don't think that has anything to do with it. Could it be the leaf spring bushings or is something loose?

Thanks for the help!  

Check from a binding slip joint in rear drive shaft.  

It could your U-joints.  

I just replaced my u-joints about 6 months ago and while I had the drive shaft out, I greased it up good. So, I don't think it would be one of those...any other suggestions?  

When you first step on the gas, the front of diff raises up from torque and shortens drive shaft a bit and if slip joint is binding it can surge or thump a bit as it breaks loose. Based on your problem, it would be the first thing I would check. Work on it 6 months ago does not mean it is 100% not cause today.  

had same problem and i found that some teeth on the pinion were broken drove like the axle was gonna break or was binding.  

I will have to look at the slip yoke when I rebuild my traclok...Other than the slip yoke, could there be something else that causes it?  

Hard to say without hearing or feeling it.  

ok, thanks!  

i had the same noise/problem with my 86 sub...at a stop light you sit there and green light, press the go pedel and could feel and hear a slight thump or quiet bang...i found that i had some play in my rr yoke on rr diff and replaced it and no more slop and no more thumping/banging noise...ring/pinion was good just a bad yoke.