Replacement rear outer pinion seal (8.6" rear)

Reprise

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Jul 22, 2015
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Just wondering if anyone had replaced their leaky pinion seal with the revised 'triple lip' seal? (GM #: 26064028 )

If it'll seal better, I'm interested - but from what I see, this seal is a two-piece design, and requires either yoke replacement or a special sleeve adapter to accommodate. That sounds like more trouble than it's worth, especially concerning getting the bearing crush / lash set correctly with a different yoke, w/o replacing the crush washer outright (requiring disassembly of the diff, and all that entails).

If anyone has put in the 'triple lip' and retained the original yoke, & no adapter... I'd like to hear from you, especially about setting the lash and how it worked out, long-term. Didn't see any mention of it when I ran a search.

Leaning toward just getting a '1st design' one piece seal from a good company like National and calling it a day. The OEM lasted until about the last year (?) or so (when I R&R'd the fluid a couple of years ago, the outer housing was dry as the Sahara). FWIW, this revised seal is considered a valid replacement for all 8.5" / 8.6" rear diffs from '99-up, not just for our 360/370 platforms.

Not a serious leak yet, but want to get it replaced before it gets that way. Thanks.
 

Mooseman

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Dec 4, 2011
25,262
Ottawa, ON
Interesting topic. If you do decide to go ahead, it would make for a good writeup on the process.

How was the wear on the pinion when you first replaced the seal? If it already had a wear groove, it may have been a foregone conclusion it would leak again.

I would say that since yours failed again after such a short time it would probably be worth the effort. In my little bit of research, I did find this kit:


Do the instructions say that the pinion has to be replaced with this seal?
 
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Reprise

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Jul 22, 2015
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Sorry for the misunderstanding... AFAIK, the existing pinion seal on my Envoy is the original. The only thing I did 2yrs ago was to replace fluid, and since my '03 has a drain on the bottom of the diff, I didn't even have to crack the pumpkin open (since it was nice and dry, and no issues with the diff, I decided to leave it alone, as much as I wanted to examine the gearset at the time)

Usually if there's a '2nd design', and the OEM specs it backward, they intend for any R&R to use the new part. So I figured someone might have gone through this (there's not a lot of 'chatter' that I can find online about using this one, vs. the old).

Here's a link to the 'sleeve' that allows re-use of the existing yoke (only place I ran across it; Yukon Gear distributes it):
Pinion Seal Sleeve

I'd be more inclined to take a chance on the new one, if I could find more evidence of someone using it. Most of the new ones are the new two-piece 'triple lip' design, but there's still a supply of the old design available (I may grab two, JIC, although the first one lasted +15yrs)
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
Ah, I see. Well, in that case, I'd go with the 1st design if the yoke doesn't have a canyon as a groove.
 

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