Just had 4:88 put in last month, now both front and rear pinion seals are leaking. Shop is replacing them without issue, other than the inconvenience to me, but why would they both be leaking?

 

They either didnt pay attention to the seal as they jammed the pinion in, they didnt lubricate the seal before the pinion was installed causing premature failure, or incorrect/defective batch of seals used.

 

That's what I was thinking, these guys know WTF , they do this stuff all the time. Typical, I'll just keep an eye on the seals if it happens again guess I'll go somewhere else.

 

The other place to keep an eye on is the front axle side seals...oil will start dripping onto the inner c from the axle tube. Those seals are even easier to damage. Dealership had to rreplace mine twice to get it to stop leaking.

 

That's the main reason I dread changing my ball joints.

 

just had my gears swapped to 488s and 2 days later my passenger side axle seal was leaking and so was my front pinion seal. The guy that did the install is no amateur he replaced the inner axle seals and pinion seal with new seals during install yet it still leaked. Brought it back to him a week later and he changed both inner axle seals and the pinion seal. Since then I dont have any more leaks from the axle seals but the pinion seal is still leaking after the second new seal. Im almost scared to call the guy to tell him because thats the second new seal he put in. It has to be something else maybe the preload was set incorrectly i dunno. Jeep drives great with no vibes what so ever just the stupid pinion leak. I may call him today to bring it back or just drive it the way it is.

 

It's very common for installers to not set the preload properly.

In order for the leaking pinion seal to be caused by improper preload, it would have to be so bad that the pinion can move around in the seal. You can see if that's the case by pulling in and out, and up and down, on the pinion.

 

Interesting, maybe I'll check that out in a bit. I really don't know much about that part of the drivetrain, it's all new to me. I just want it done right, seems like my $2200 could at least give me that much. I don't have any noticeable vibration but for both to fail in the first 500 miles, obviously something is wrong.

 

After an accident a repair shop change out my axle tube, put in new seals but didn't pre-load pinion properly. Seal started leaking within a week. Job was so bad I could rotate the drive shaft and the pinion would move in and out the differential.