The V8 Owners Forum -

I am about to enter into the unknown; fitting a jag diff into my P6

I really wanted a 2.88 LSD jag diff, but couldn't find one anywhere, so ended up bidding on entire axle on ebay. Surprisingly, I won the auction I can't remember how long I've had this and don't have many ideas on how to fit it yet (some but not many). I have however, taken it apart



Diff out and ready to fit (ok it needs cleaning and perhaps an internal inspection)





Now the thing is, I have read up on the diff and have scared myself with things like ramp angles, seized LSD, etc.

So, any advice?
Do I just remove the rear cover and clean it out, refit and fill with oil?
Any way of testing the LSD?
Anything else I need to check?

By the way, anyone want any of this lot, make me an offer



Richard

First thing I would do is remove the calipers and discs and then check how smooth it feels when you turn the pinion. There should be no roughness. Both output flanges should be turning equally if it's a power lok diff and there should be a tag with POW LOK stamped on it under one of the rear cover bolts. Another tag will have 2.88 on it.
To test the effectiveness of the limit slip of the diff, lock one of the output flanges with a bar across the studs and use another bar to lever and rotate the other flange. You should be just able to turn the flange using say a 2 foot long bar. If little force is needed to rotate the flange then the plates in the limit slip are well worn. If you cant turn the flange at all then the plates may be seized. You should not be able to feel any rotational slack movement between the two output flanges.

Just out of interest, what model Jag is that lot from?

Chris.

Likely to be out of a v12 xjs.

Cheers Devonman, I'll give that a go tomorrow. I did drain the oil today and was going to remove the rear cover tomorrow for a quick visual check, no more than to check the teeth are ok, and check there's nothing lying in the bottom of the casing

It does have a tag with 2.88 on it, as well as another with PL.

I was told when I bought it, that it came from a 1985 XJS.

Do you know if it's just a straight EP90 oil?

Cheers

Richard

You should use an oil designed for limited slip diffs.

I've got the calipers off, along with the discs, which are basically scrap (the discs, not the calipers). They were very fiddly to get at, heaven knows how difficult they are to get off when they are still on the car. I'll be rebuilding the calipers, new pads and discs so I can hopefully fit and forget. Then half an hour with a wire brush, and it looks like this:-



The rear cover is off and I've had a delve inside. Turn the input pinion by hand and both output shafts turn smoothly and freely. Catch hold of one of the output shafts, and try to turn the other one, and I can't. Lock one of them with a bar and then try to turn the other with a two foot long bar, and I can do it but there is a good resistance and everything is very smooth with no roughness at all. I have turned the crown wheel round a few times and carefully inspected it, no chips or marks on any of the teeth. All seems well with that, within my limited knowledge of diffs, so I'll cover it up for now and fit it as it is when I'm ready



I've also managed to get Sparky up on four ramps, so I can get underneath and start measuring and making plans of how to fit the diff. The ramps are all the same height, so any angles I'll be measuring should be the same. I hope



Now, there is a a sensor on the back of the diff. Anyone knows what it does and do I need it?

"there is a a sensor on the back of the diff"

Speedo sensor, 10 pulses per wheel rev from memory.

Cheers Russell, I'll bin that then.

Couple of reads here that might help

http://irsforum.boardhost.com/index.php

http://jaguarxjsresto.blogspot.co.uk/2015/03/

https://www.jalopyjournal.com/forum/thr ... er.556832/

Thank you JSF55, there's certainly some interesting stuff in those.

I know I'm jumping the gun here, but I've been looking at brake bias proportioning valves. There's some real cheapies, which I'll not bother with, some from Wilwood at around £50 or so, OBP which look to have the same manufacturer, Tilton ones at just over £100, and some really expensive ones.

Anyone use any of these, are the Wilwood ones reliable?

Richard

Off topic, but that is a beautiful car!

Chris.

ChrisJC wrote: ↑

Thu Jan 18, 2018 7:26 pm

Off topic, but that is a beautiful car!

Chris.

Thank you, I built it myself Well ok, Rover built it in 1975 but I rebuilt it myself.

Build thread is over here - http://www.classicroverforum.net/index. ... ork.26263/

Richard