This is in my 04 rubi, i started hearing a slight moaning from my rear 44 on the way back from spring creek this past weekend. I pulled the cover but didnt see anything out of the ordinary. With the driveshaft removed, i can grab the pinion and rotate it back and forth - the pinion depth changes! if i rotate it clockwise it actually comes out away from the diff about 1/16 - 1/8".
Any ideas?

Lose pinion nut? Whens it moan? All the time or just on accel or decel or...

no, pinion nuts tight. Only moans on accel. talked to a friend who has been building diffs and been an ase master for like 30 years, he thinks bearings are shot

Nothing against your bud, but ASE means nothing to me. Diffs aren't rocket science, but there are few that understand them and know how to work on them correctly. That mostly means just following some basic steps and being anal about it.

If the nut is tight and the pinion is still moving in/out 1/8" (.125"!), then the bearings are shot and you should see metal in the bottom when you took the cover off. Because that would mean the cage/and or needles are completely toast. That kind of shit doesn't happen without leaving metal.

I'd check that nut again. If it is indeed tight (200 ftlbs), then it was either a poor setup or it was loose at one time but now you have something jammed in there keeping it from tightening up. Which is completely possible...

OK i'll check the pinion nut again. there were zero metal shavings in the housing when i pulled the cover, so does that completely rule out a busted bearing?

OK i'll check the pinion nut again. there were zero metal shavings in the housing when i pulled the cover, so does that completely rule out a busted bearing?

No. The only way you can rule it out is to take it apart and inspect the bearings. But typically if something is coming apart, there are going to be metal shavings/chunks in the oil.

If the nut is indeed tight, you may end up pulling the pinion seal and having a look behind the outer bearing and see why you can't tighten it. At that point, you may as well pull the carrier and the pinion so you can look at the inner bearing as well.


How long have you been running on this setup? Is it a fresh install?