the other day i noticed the pinion seal had let go and was doing a pretty efficient job of rust proofing the underside of my pickup. when i got underneath to investigate i noticed a substantial amount of play in the pinion. when you wiggled the driveshaft it seems as if the pinion is moving forward and backward, and when you grabbed ahold of it you could wiggle it up and down. i figured the bearing had lost its lunch so i tore into it to further diagnose the problem.

upon tear down and inspection it appears that the inner pinion bearing was actually spinning on the pinion itself. with the pinion out and in my hand there was probably an 1/8" gap between the back of the bearing and where it was supposed to be. im assuming that it moved this much when i removed it, i was able to use a small screwdriver and pry the bearing down the shaft and off the pinion the rest of the way.

it appears someone has been in there playing around, as one bearing is a Timken and the other a National. my question is, did the bearing come loose and spin simply because the preload wasnt set right or are there other issues here?

I can't say that I've ever seen this happen before, but then again I haven't been turning wrenches all that long. If I put new bearings in and shim it correctly will i be alright or is a catastrophe just around the corner?

 

The feces is visible now. Somewhere there should have been a shim between the big bearing and where it seats on pinion. The mice have been busy. Based on your statements and my imagination, I would suggest a new ring and pinion, bearings and proper setup by qualified pesonell with required tools. When pinion teeth rub against ring gear in a loose condition, wear results to both pieces.

 

there was a shim between the big bearing and the pinion, its chewed up but was still there. i dont think it was spinning that long because the pinion feels very smooth, my eyechrometer tells me that its alright but i havent actually checked it out yet. and the back of the bearing appears to be undamaged, actually neither bearing appears to be bad.

i should have taken pics as they would be much better than my description. just curious if anyone has seen this before?

Im going to put new bearings on and put it back together. If it takes a major dump, i wont be out much. I want dana 80 with 3.55's anyhow

 

eyechrometer I like that!!

 

A very good friend who happens to be the best baling wire & bubble gum mech that I know has done several gear sets with no more than the as issued mark one eyeball & has yet to have one fail. That said I do admit to perfering to have all the required tools when needed just makes me more at ease.

 

I would not expect it to last long if the bearing has been spinning on the shaft....mostly likely it will again. It might get you by for a while, but dont plan on 100K. I would start searching fleabay for that D80 tonight .