Hi I have a 2014 XJR and on a couple of occasions I’ve heard what I can only describe as a slight rumble from the rear. It happens when the car has stood overnight and just after moving off down hill with very light throttle. Any ideas suggestions as to what to do?

 

I also have a 2014 XJR (Tuned W/ 630 HP) and I just recently changed the rear diff oil at 42K miles. Black as hell and looked terrible!
Maybe not too bad as these cars have Carbon Fiber friction surfaces and we get what's known as "Carbon Shedding" which does turn the fluids very black.

So my recommendation as a fellow XJR owner is change the rear end fluid NOW! It takes less than 30 minutes as we have both a drain plug and a fill plug (Thank you Jaguar!).
I researched this and used Redline 75W-90 #57904 which meets GL-5 and it meets the Jaguar recommended Castrol SAF Carbon and Castrol SAF-XO specs.

Note also that Jaguar fills the rear diff by volume and NOT by oil dribbling out the fill port. Which is how ALL other rear diffs are filled. Just another weird bit of Jaguar stuff!
But to be fair ours take 1.2L so buy two 1L jugs. The 1.2L is pretty much all the way up to the fill port anyway so I think they are splitting hairs here with the volume?

I also plan to change this every 20K or so. It's just too cheap and easy to do.
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[QUOTE=clubairth1;2210498]I also have a 2014 XJR (Tuned W/ 630 HP) and I just recently changed the rear diff oil at 42K miles. Black as hell and looked terrible!
Maybe not too bad as these cars have Carbon Fiber friction surfaces and we get what's known as "Carbon Shedding" which does turn the fluids very black.

So my recommendation as a fellow XJR owner is change the rear end fluid NOW! It takes less than 30 minutes as we have both a drain plug and a fill plug (Thank you Jaguar!).
I researched this and used Redline 75W-90 #57904 which meets GL-5 and it meets the Jaguar recommended Castrol SAF Carbon and Castrol SAF-XO specs.

Note also that Jaguar fills the rear diff by volume and NOT by oil dribbling out the fill port. Which is how ALL other rear diffs are filled. Just another weird bit of Jaguar stuff!
But to be fair ours take 1.2L so buy two 1L jugs. The 1.2L is pretty much all the way up to the fill port anyway so I think they are splitting hairs here with the volume?

I also plan to change this every 20K or so. It's just too cheap and easy to do.
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. Thanks for this I’ll certainly change the diff oil when this ‘imposed isolation’ period is over.