Found lots of tips here so I think I am ready. Got all the parts. What grade diff oil to use as I might as well change it while I am there.

 

I used 80/90 gear oil in mine last year. I don't have limited slip though.

 

Yes, this is what I will be using but I need to verify LSD first. Got the diff output shafts out right now so I can't verify till they are installed back on. Thanks for the reply.

For future: Opposite spinning wheels are normal and both turning same direction is LSD.

Leo

 

A black X or cross through the colored diff ratio label will indicate Limited Slip!!!!

bob

 

Good to know Bob. Where is this label located?

 

Hi Leo,

The label is on the rear cover of the diff, usually near the metal tags that show the diff part number and gear ratio. On our '93 it was on the right side of the right-most cooling fin. The parts listing at jaguarclassicparts.com tells what the different labels indicate.

In case they may be helpful, here are links to photos of the output shaft bearing replacement on our '93. I'm sorry the large images are currently down at Jag-Lovers, but you can still see the thumbnails and descriptions:

XJ40 Differential Output Shafts Part 1 of 2
XJ40 Differential Output Shafts Part 2 of 2

Regarding oil, I've used the Lucas and Mobil 1 gear oils with no issues whatsoever. I especially like the Lucas Synthetic 75W-140, which has a cold temperature viscosity similar to the oil originally specified by Jaguar, but much better high-temperature protection. Another option is the Lucas (non-synthetic) 85W-140, which may be an even better choice if your diff has developed excessive backlash.

Cheers,

Don

 

I looked everywhere for a tag and saw only one on a bolt but it's so far up and my phone couldn't even get there. Anyways, both wheels turn the same direction, so I got a LSD.

I have a couple bottle of 75/90 full syn that was going to go in my GMC truck but never used it. It says it's good for LSD and Posi on the label. Should I be ok with the grade weight? Either way, what is the capacity? Do I need more than 2 quarts?

Leo

 

Hi Leo,

The original oil specification for the Powr-Lok differentials was SAE 90 Hypoid gear oil that met the API GL5 specification. Your 75W-90 may be just fine, but you might do a little research to see if you need to add a limited-slip gear oil additive. I know Lucas claims some of its gear oils require no additive in LSDs.

Jaguar states the capacity of the differential at 2.1 liters, which is 2.22 quarts, so your 2 quarts may not completely fill the diff.

Cheers,

Don

 

.

 

It would be so much easier if Jaguar just had a fill plug at the “full” level. Even an idiot couldn’t overfill the thing and only a bigger idiot wouldn’t underfill the diff. My 2nd V6 S F-Type had no diff problems after 60,000 miles. My 1st V6 F-Type S went 54,000 miles without an issue. Neither was tracked nor did I ever do burnouts. The biggest problem was the “Low Batt” warning after the annual state emissions test. Easy but annoying fix. Doesn’t happen on our other Jags.

 

Hi Ichi Ban,

You have posted in the forum for the XJ40, whose GKN Salisbury differential does have a fill plug at the full level. Did you intend to post in another forum?

Cheers,

Don

 

Ah, yes. I did.