When I first got my truck last year (146K on the odometer) I was feeling a little clunk-clunk every time I started from a dead stop (or a very ssslllooowww rolling stop from a light). It felt like a tranny hesitation but I couldn't find anything wrong. I found a post that described this and recommended that I grease the slip yoke. I marked the shafts for alignment, disassembled at the u-joint (fwd or aft depends on your year, I think aft for the earlier years IIRC). There was very little play in the shafts and the u-joints were solid. I greased the slip yoke (there was almost none in there before I added grease) and the problem was gone.

It is worth a try. I also thought I was in for the beginning of the end for my transmission and wallet and all it took was an hour and some grease. Needless to say it was well the try before driving to John Wood. Now I grease the slip yoke once a year whether it needs it or not (as the shaft moves inside it pushes the grease out of the grooves into the rear expansion area) to keep it from happening again.

It's worth a try IMO. At least you can rule out any driveline chatter. Best of luck and hope this helps.

 

Grease that slip joint.

It works wonders!

Pop

 

It's been less than a year since I had the driveshaft balanced and the slip yoke lubed. But when I get back to Charlotte I promise I will do it again. It is the strangest problem. It only does it about half the time, does not seem to do it at all if I leave the dead stop with a little authority instead of my usual fuel sipping practice of slowly accelerating to speed. I am at a loss really. If it is ring and pinion slop as it looks like it may be, you would think there would be a clunk, or a sort of parts slamming together????

 

I think if it were excessive ring and pinion backlash you would be getting considerable gear noise

 

You'd certainly think so, along with a clunk when changing from forward to reverse.

 

Sounds exactly like what I was feeling. It's been a year since you greased your slip yoke so I wouldn't be surprised if most of the grease has been pushed from between the splines now.