I have a 2001 screw with the 9.75 ear end. The passenger side seal had been leaking for awhile and finally blew out (pouring oil out) a few weeks ago. I replaced the seal, checked the axle for burrs or damage and checked the vent line for blockages. The seal has held fine for the last few weeks with city and highway driving. Today, I checked the wheel and found a small amount of oil drilling down, maybe a few drops.

Why do I keep having seals fail?

 

Axle bearings collapsed?

 

You have to replace the bearing if you keep destroying the oil seal. I went through this. But when you go to buy one, make sure your 9.75" axle either has the tapered ends at the wheel end of the axle. Some of the 9.75" rears use the 8.8 bearing and seal. Also, buy yourself an extra cross pin for the differential, often they break off.

 

It hasn't leaked since that once instance. I was talking to someone else that thought that it may have "burped" the oil trapped when I installed the seal. Since I lubed both the seal and axle when installing it, it's possible that there was some oil trapped in it that finally worked itself out. I'm going to take a nice, long drive this afternoon to heat the oil up and see if any more leaks.

 

also make sure your vent line isnt plugged up

 

Vent line isn't plugged. I blew out the line and passed a hex key into the housing. I ran it for about 4 hours on the highway yesterday and no leaks. There was a small amount of "oily water" at the bottom of the dust cover but I think that has to do with the slush washing everything clean. I'll keep an eye on it for awhile but I think the problem is fixed.