Looking at the XJ40, 1991 spare part list, it obviously shows a limited slip diff...

But nowhere does it say anything about using Limited Slip diff oil...

Does anyone know if I should use the recommended API GL4/5 oil, or if I should go for the limited slip diff oil?

Or do the XJ40 com with both alternatives?

Tanks in advance for any suggestions...

 

Hi Roland,

If you have an LSD, Jaguar does specify an LSD friction modifier additive, but I think it is to be added to the same gear oil weight as the open diff. Have you checked your owner's manual or the Workshop Manual?

Have you checked the model number tag on your diff to confirm it is an LSD? The part number may be stamped into a metal tag secured by one of the cover screws. The ratio may be stamped on a second metal tag. I am under the impression that not many U.S. cars were equipped with the LSD. Our '93 VDP has an open diff. Hopefully one of our other members will know which cars came with LSDs.

See photo 6 in the album at the link below for the part number and ratio tags on our '93:

Welcome to Jag-lovers - Members Photo Viewing Page

Cheers,

Don

 

Just use gear oil with the additive OR buy the additive from GM or a parts store.

bob gauff

 

Jaguar LSD has a BLACK X through the colored decal on the back of the diff.

bob gauff

 

Many thanks for your comments and pic's!

I'm hoping one of the upcoming days, I'll be able to crawl under and check the tags and lift one rear wheel and see if it will turn easily or not...

But wouldn't it be possible to use the special LSD oil, which I assume has the additive included, regardless which diff I have.

I'm thinking that our climate in Sweden makes it more likely that most cars are equipped with LSD here.

 

Bob, correct me if I'm wrong, but if I recall correctly the test for an LSD is to raise both rear wheels, rotate one wheel, and if the other wheel rotates in the same direction it's an LSD. With an open diff the other wheel will spin in the opposite direction.

 

Don You're absolutely correct!

It also works if you have gear in neutral and one wheel in the air...

If you can turn the wheel, it's a regular diff, if you can't turn the wheel, it's an LSD.

 

Perhaps I should add, "if you can turn the wheel easily" .

If it turns with some force it can still be LSD, but suggests that the wrong oil might have been ued at some point.

 

This is the stuff you ideally need , it was designed to Jaguar's specifications for the xj40 i believe , bit hard to source these days so you might have to use whatever you can get ,

 

The XJ40 open diff is a standard GKN Salisbury unit based on the Dana 44 which Jaguar used in the E-Type and other models from 1961. It's an excellent and robust design but there's nothing particularly special about it, so any good gear oil in the proper viscosity range seems to work. I've used Valvoline synthetic 75W-90 and 85W-140 and Lucas synthetic 75W-90, all with no apparent problems:




Cheers,

Don

 

Yes , of course , i meant for LSD's

Derek.

 

If I recall correctly, Jaguar originally specifed Shell Spirax TS90 for both the open and LS diffs, but in the LSDs they also specified the use of an additional friction-modifier additive to prevent chatter.

If you use a modern gear oil in an LSD, you should also use an additive.

Lucas claims their diff oil does not require an additive in an LSD, but I would personally use one anyway.

Cheers,

Don

 

Here we have special LSD gear oil with the additive included.

I agree, I would NEVER use any regular gear oil in an LSD axle.

 

The best LSD modifier is from Ford. Small bottle and all contents go into diff. with GL-4 or 5 fluid. Ford dealers carry it and it will be blue in color. The pink stuff you buy at parts retailers does not work as good. If you hear or feel a clunking or jerking get the Ford stuff.