2001 XKR Differential oil
 

My car has developed a whine in the differential. It is the original oil and although my mechanic indicates the fluid level is good, I'm pretty sure the oil has degraded in 17 years.

Problem is only Jaguar sells the specialty oil at $100 per liter. Is it necessary to use this oil, based on the oil number I believe it is 90 weight oil just not sure if it has special friction modifiers.

Is it advisable to use standard differential oil for around town driving. I dont think the oil change will fix the whine just dont want to destroy the differential.

Thanks

Gary
n17gary

Do a search and you will find that the subject has been covered in multiple threads. Many of us use 75W140 synthetic.

and you are liking it fine I'm guessing ? Are we talking about the Mobil 1 75w-140 LS (limited slip) . I've used that in many vintage Ford rear ends, that see extreme use, and it's worked very well.

Z

Update on my whine in the differential--Had my mechanic drain and refill it with Red Line 70W90W as it was the product recommended on the Red Line site.

I still have the whine when I take my foot off the gas at slow speed. Mechanic could not offer any timeline as to service left in the Diff. Any thoughts on just running as is now. I can deal with the noise just don't want to lock up while driving. I have 108K miles on it.

before tearing into it, I'd try a synthetic 75w-140, Mobil 1 makes a good one and there are many others.

The chances of you locking up the differential gears with the symptoms you describe is very remote, You'd have to break a tooth and since you are not drag racing, that's not going to happen.

The whine will get progressively worse as the gears wear and the tolerances increase. Admittedly annoying. But you can drive it that way for tens of thousands of miles without breaking anything.


Z

Are you sure it's the diff and not one of the rear hubs or bearings?

Differential whine is often the carrier bearings going bad. Only a rebuild is going to fix this. Oil is nice but it cannot fix the bearing tolerances.

You say it wines with foot off the gas at LOW SPEEDS only? If you are IN low gear when this happens, and it doesn`t happen in any other gear, it could be the planetary gears. They are very small teeth and can go bad if you tow heavy trailers or if you are a lead foot off the line.