Pinion seal leak...

you could retighten the pinion nut and re-stake it but this is only a temp fix, you need to get it fixed before you get slack in it and ruin the ring and pinion (like I did)

 

It usually is the pinion seal, not much to it to fix. Take the shaft off, undo the nut, slide the flange off and replace the seal. Took me 30 minutes to replace both.

 

Be sure to properly stake the nut when done - very important! Also you might want to smear a bit of silicone caulk on the splines inside the companion flange before you push it on. This keeps oil from leaking through the splines.

 

I have the same thing on my BJ60 :'( I was able to unstake and tighten the staked nut about another 1/8 turn before I hit 140ft/lbs torque again. It wasn't making much noise but I've had my truck for nearly 15 years and I know how it's supposed to sound. How much time do I have before I need to do this? I was just in the axle last month to replace a leaking axle seal so I'm not too anxious to go back in Besides bearings, seals and gaskets are over $200 (2 pinoin bearings, 2 carrier bearings, pinion seal and diff gaskets).

 

[quote author=cruiser_guy link=board=1;threadid=5112;start=msg39624#msg39624 date=1063160644]
...Besides bearings, seals and gaskets are over $200 (2 pinoin bearings, 2 carrier bearings, pinion seal and diff gaskets).[/quote]

You might be better off looking for a used low-mileage complete diff for that price. Unless your good at settin' up gears I guess... Anyway, I just traded both of my stock 3.70 diffs off--but they were in EXCELLENT condition for bein' outta a 1984. No play or leaks at all. I'm sure there are more in better condition... Just my opinion anyways...