So here goes, My Dana 35 (3.55 with 180k on it) whines like a s.o.b. under load and when you let off the gas the noise is completely gone. I was thinking the Ring and pinion or one of the bearings were shot. Took the cover off and theres no metal shavings or anything and all the gears look mint. Fluid is super dark and thick. The only thing I noticed is that if I push the wheel back & forth from front to back an inch or so the gears on the diff cross shaft seem to wobble a bit which Im not sure is normal (although they do not look damaged) see pic. Also if I spin the wheel as if the jeep was moving forward, there is no noise at all. If i turn the wheel backwards I can hear a bearing noise (click, click, click) which sounds like its coming from the pinion bearing inner or possibly outer. The pinion oil seal is leaking a bit as well which may be unrelated. I almost wonder if it could be a wheel bearing?.. but the noise is gone if you take your foot off the gas so...?

Everyone says just to swap the entire rear out but I wouldnt mind learning how to replace the parts needed... basically rebuild the inners that I need. I am very mechanically inclined and have done plenty of motors, transmissions etc on cars and bikes so Im sure I can get it done. I dont do any crazy mudding through rivers or 6 feet of mud... maybe 3 feet of mud. haha, No plans for the immediate future for anything over a 4.5" lift. Just want it to run properly without the screaming rear that sounds like its going to grenade... ANyone have any ideas?

 

More than likely the pinion seal is leaking because the bearings are shot. Use a pry bar and attempt to move the pinion flange forward and then push it back. If you can move it at all the bearings are toast, if you caught it early the ring & pinion may still be serviceable. The spider gears do have a little slop but only come into play during a turn.

 

It's not that the job is overly complicated but it does require special tools and possibly a lot of patience to get it right. You could be disassembling and reassembling multiple times to get the right gear pattern. If you don't have the tools it can be cheaper and easier to replace the whole thing.

I had similar bearing issues and after looking at the price of bearings and not having access to the right tools anymore decided to look to replace the whole unit. I picked up a complete rear, drum to drum with leaf springs and e-brake cables still attached with only 60k miles for $150. I also took out the old axles for spares before trashing the bad rear.