I don’t have the dimensions, as shop has the pumpkin, I am wondering if there were any differences in pumpkins through the years, as the car is an 83 xj6 but it had pl, not just swapped in, had the tag too, so might have come from a different year or model, as I am told the xj6 with a pl is a rare animal, plus previous owner had done a bunch gasket matching on both intake and exhaust alsoade
of head along with manifolds ( plus one of the stub axle bolts had been broken off by someone

 

Rare animal, yes. I can almost promise that the PL diff was swapped-in, presumably by an enthusiast previous owner. If so the diff probably came from an XJS, as XJSs had PL as standard issue.

As for different pumpkins, well, there's the GKN/Salisbury-manufactured versus Dana-manufactured dilemma. The Dana manufactured diffs had some unique parts, including seals. Over the years I've heard of others having a hard time finding replacements for some of them....although the specifics are a bit foggy at the moment. Others here will know.

The Dana-manufactured diffs are easily recognizable by lack of a drain plug at the bottom.

Also, among the GKN/Salisbury diffs, there were some design changes in the mid/late 70s, I think, which may account for your seal dilemma.

Let's hear what others have to say.

Cheers
DD

 

To the top…

 

I measured a diff I have apart. For the pinion seal you need a bore size of 3-1/8" and a shaft size of 1-7/8".

 

Thank you, will give that a go

 

Been googling like crazy, seal I was told originally was national 5778. Daze cars and a few other places are saying 15788. Maybe first guy got it transposed….

 

5778 is a National/Timkin number. The other number shows up on their interchange list as a competitors seal that crosses over. Here is the seal: https://www.rockauto.com/en/moreinfo...=1121&jsn=1121

I think Daze was starting with an E Type rear end, and the companion flange is a different diameter than the later XJ cars. The 5778 seal is for an earlier differential. The bore of the housing is the same, the pinion flange is different.

This is probably the seal you want, SKF 18891 https://www.rockauto.com/en/moreinfo...sn=643&jsn=643

If you do order from Rockauto, I have a 5% discount code anyone can use. It's 199219259123292460 and put that in the "how did you hear about us" box at checkout under the shipping options. Code expires May 8, 2022

 

15788 worked !!!! Got it back! Guess what I’m doing this weekend!!!

 

Finally got it all reassembled and back in the car! Dear lord, what a difference!!!! Acceleration is ight and day, and it pulls until it breaks loose, gonna have to learn to launch it better! Lol especially since im
going back into engine (lt1) with ported heads and intake!