Rear diff pinion seal - replaced and now it's leaking more!

[JasonPAtkins]

Hi folks,
I just got done doing the rear diff pinion seal, diff oil change, and one of the rear axle seal/bearing combos. The diff is leaking from the pinion seal now more than it was before, when it was just weeping, haha... Not the direction I was hoping to head!

I suspect two things:
1) Maybe I overfilled the diff. I used the measurement I found online (which I can't remember now, maybe 2.5qt?), but the last little bit did spill out, which means it was filled to the filler hole, not the 15-40mm below that that GM specifies as the full level. So maybe the level being too high is making it slosh against that seal more than it should.

or

2) I installed the new seal into a clean bore, but did so with no RTV. The seal doesn't come with any boretite like the axle one does, and after reading a bunch of forum posts and anecdotes, couldn't find a conclusive argument for or against, so I left it off. Maybe that's why it's leaking?

I did check the breather hose, and it's unrestricted.

Thanks!

 

[ivin74]

I did my front pinion seal and had the same issue. I removed the new seal and compared it to the old one and bingo O'reilly's gave me the wrong part. After further research the box the part came in had the wrong seal so it was not O'reilly's fault. They exchanged it and gave me the correct part free of charge.

 

[JasonPAtkins]

Hmm.. this one came in a sealed AC Delco bag and sure looked the same. Maybe I just got a bad seal. I'll order another and try it again. I'll be much happier to replace the pinion seal than the axle seal which requires opening up the diff - so if one had to go bad, I'm glad it was this one. (Though I haven't pulled that wheel and brake yet to find out if that one's holding yet, so I guess it could still be both, lol.)

 

[ivin74]

Hmm.. this one came in a sealed AC Delco bag and sure looked the same. Maybe I just got a bad seal. I'll order another and try it again. I'll be much happier to replace the pinion seal than the axle seal which requires opening up the diff - so if one had to go bad, I'm glad it was this one. (Though I haven't pulled that wheel and brake yet to find out if that one's holding yet, so I guess it could still be both, lol.)

Lessons learned for me was always compare the seals before installing them.

 

[Buzzcut]

Hi folks,
I just got done doing the rear diff pinion seal, diff oil change, and one of the rear axle seal/bearing combos. The diff is leaking from the pinion seal now more than it was before, when it was just weeping, haha... Not the direction I was hoping to head!

I suspect two things:
1) Maybe I overfilled the diff. I used the measurement I found online (which I can't remember now, maybe 2.5qt?), but the last little bit did spill out, which means it was filled to the filler hole, not the 15-40mm below that that GM specifies as the full level. So maybe the level being too high is making it slosh against that seal more than it should.

or

2) I installed the new seal into a clean bore, but did so with no RTV. The seal doesn't come with any boretite like the axle one does, and after reading a bunch of forum posts and anecdotes, couldn't find a conclusive argument for or against, so I left it off. Maybe that's why it's leaking?

I did check the breather hose, and it's unrestricted.

Thanks!

If it has high miles could have a groove wore in the yoke. If so replace the yoke or put a metal sleeve over it to repair it. Sorry I can't remember what they call them. Also make sure that nut is tight. I had a new seal leaking after a few days on my GMC truck. I replaced the seal and made it tight. Impact wrench tight. No leaks afterwards.