I have a 1999 XLT with a stock positraction rear axle. The vehicle has approximatly 160,000 miles on it and has, for the most part, been properly maintained.

I recently took it into a local mechanic (whom I believe is reasonably competent and honest)for an engine oil leak (leaking oil filter adapter bracket, which was repaired without further incident). while I had it there, I mentioned that the rear axle seals were leaking, and could he fix those. He later called me and told me that the rear pinion seal was leaking as well. I authorized repairs for both. It was reported to me that all the repairs had been completed and that everything looked good.

I then proceeded to take a rather lengthy road trip, 2600 miles in one week. (towards the end of the trip, i noticed a little bit of rear end noise, and made a mental note to call him up and mention it. Upon my return, I turned the vehicle over to my wife and kids (as many of us must reluctantly do) and din't drive the vehicle for a couple weeks. They put another 400 miles on it, with out comment (as might be expected from one's wife and kids).

A couple of days ago, I drove the vehicle and noted that the rear end noise was considerably more noticeable. I crawled under the vehicle and noticed that the entire differential case, and the underside of the vehicle was coated in oil, and that there was a hose (breather?) that was loose. I decided to drive the vehicle to the mechanic the next day. On the way, (with very noticeable rear end noise, I stopped off for coffee and discovered that I couldn't maneuver in the parking lot; the differential appeared to be a locker now.

Eventually, i got it to the mechanic, and, after tearing into it, his statement was " the pinion bearing is pretty much destroyed, and possibly the carrier bearings too, and there is a lot of metal floating around. I don't know whatever could have caused it."

Is it just me? or is it kind of suspicious that I only started experiencing these issues after he worked on the differential and replaced the seals? Is there something that he could have done /screwed up on that lead to the premature demise of my pinion bearing? I am a reasonable person, and a mechanical engineer, and I understand that mechanical components don't last forever, and that there could be a variety of reasons why this failure may have occurred, but 160,000 miles doesn't seem like a stretch but it seems to me like this should be a mechanics warranty issue. I am told that, if the Pinion is messed around with, and the crush washer is not replaced or properly torqued upon reassembly, that it can totally mess things up. I don't want to screw anybody over, and I kind of like this mechanic, but i don't want to pay for his screw up.

Any comments/suggestions as to how I should proceed?

 

When the pinion seal is replaced, the re-alignment of the ring and pinion gears is critical. The pinion must also be torqued properly but it's no coincidence that this happened just after the repair.
The wheel seals is an easy thing, the pinion seal must be completed by someone who really knows and understands the tolerances required.
Go back and make this guy fix it.

 

The process isn't that difficult for someone wanting to do it right. But if you are in a hurry, watch out.... sounds like he is possibly less than competent or less than honest. A leak is just a bother. A poorly installed pinion seal is a mess.

 

A few years back, my neighbor did this himself. Without proper re-alignment, the rear end lasted about 30 minutes.