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Newly rebuilt diff - pinion oil seal leaking
JekRankin - 23/10/19 at 10:05 AM

Had my 7” Sierra diff rebuilt by a well respected specialist. Quaife LSD was fitted, and bearings and seals were replaced. On the first drive I noticed the pinion oil seal was weeping. Pretty sure it’s passing the seal, and not the splines as others have reported previously.

Two questions then;
1 - any possible causes, other than a botched install, which seems unlikely given they rebuild these things daily. Blocked breather or overfilled with oil perhaps?
2 - I’ve got a replacement seal. Is it feasible to swap this with the diff in the car? Access looks pretty good with the prop disconnected.

Jek

CosKev3 - 23/10/19 at 11:05 AM

If you've got access to a ugga dugga gun it will be easier, as the retaining nut will be tight and it's hard to hold the diff from turning if you use a breaker bar.
How much oil is it leaking?
Only other thing it could be apart from a faulty seal is the surface on the drive flange is scored/pitted etc where the seal sits.

JAG - 23/10/19 at 11:11 AM

quote:

Had my 7” Sierra diff rebuilt by a well respected specialist


Surely you take the car back and ask them to help. They must be prepared to help as they are "well respected"

nick205 - 23/10/19 at 12:33 PM

Is the rebuild not covered by a warranty?

And if it's been rebuilt by respected people then surely they should have checked the components for any corrosion, scores uneveness - faults that could cause leaks.



[Edited on 23/10/19 by nick205]

JekRankin - 23/10/19 at 02:41 PM

Yeah I’m sure the company who built it would be more than willing to help, just trying to avoid the hassle of removing the diff entirely and shipping it down to them.

Warranties for this kind of work can be difficult I guess - it was probably 2 years between the diff rebuild and the completion of my car.

The other reason for wanting to remove the seal is so I can check the seal surfaces myself.

[Edited on 23/10/19 by JekRankin]

mcerd1 - 23/10/19 at 07:01 PM

u2u sent



[Edited on 23/10/2019 by mcerd1]

DJT - 24/10/19 at 12:49 PM

quote:
Originally posted by JekRankin
Had my 7” Sierra diff rebuilt by a well respected specialist. Quaife LSD was fitted, and bearings and seals were replaced. On the first drive I noticed the pinion oil seal was weeping. Pretty sure it’s passing the seal, and not the splines as others have reported previously.

Two questions then;
1 - any possible causes, other than a botched install, which seems unlikely given they rebuild these things daily. Blocked breather or overfilled with oil perhaps?
2 - I’ve got a replacement seal. Is it feasible to swap this with the diff in the car? Access looks pretty good with the prop disconnected.

Jek


I had the same! Didn't want to do another round trip so they sent me a new seal and I fitted it myself. No problems since. No idea why their fitting did not work though.

JekRankin - 24/10/19 at 12:53 PM

Oh that’s quite interesting....Did the new seal sort the leak ok?

DJT - 24/10/19 at 06:21 PM

Yes, sorted no problem. We'll actually is a bit of a faff getting the pinion nut off in the tunnel. Since then I have an impact wrench. When refitting I did smear some RTV sealant around the front face of the seal/housing - probably not needed. Good luck with it.