'89 M998 poping when accelerating in a straight line.. diff?

[ke6rwj]

We've been driving this truck for a while and no real issues. We started getting popping on turning, but recently its also started popping rapidly when accelerating forward and backwards. I replaced all 4 axles with new ones and it still pops. Its a rather fast pop also, sounds like its in the rear. My instinct based on the sound its in the right rear.

Here's what I've done.
- Replaced all 4 axles with new ones
- Checked for loose brake caliper/pads/bolts
- driveshaft joins seem tight, nothing obvious in suspension
- drained rear diff oil nothing major on plug or came out with fluid. Just very fine dust on the plug.
- no leaks to speak of..

Is it possible the diff / ring pinion is slipping?
Other possibilities?

Thoughts?

-- Chris

 

[DREDnot]

I would chock the wheels and drop the diff end of each driveshaft so there is no load on it and then check(and grease ) all the u-joints. Often the u-joints will seem good when installed but are in fact seized or wollered out and it is only noticeable when one end is removed.

If all is good there then jack up each diff in turn and give it a few turns to check for shenanigans while its isolated from the drivetrain before reinstalling the driveshaft

 

[Gcelevator]

Pillow bearing in the front drive shaft?