I've got an annoying whine form the rear of the car at low to medium speeds.

It only whines when my foot is on the accelerator. When I take it off the whine goes away.
When I take the car out of gear the whine goes away.

I have 50,000 miles on a 2004 car.

Is it the differential?
Does the oil need changing?
If so, how do you do that?

 

Tell the rear seat passengers to be quiet and just enjoy the ride!

 

That's typical, coming from an XK driver!

 

x20 (8 kids + 12 grandchildren).

 

The only two things that can cause a whine at the rear of the car are the wheel bearings, and the differential. Your symptoms indicate it is not wheel bearings as the noise disappears when you remove the drive torque. Wheel bearings would be noisy regardless of power-on or off.

Hard to believe it is a diff on a 50k miles car, though.

 

Do check the fluid in the differential.

 

That's what I thought - now apparently the diff is a sealed unit.

I'm hoping it could be transferred noise from a noisy belt though.

BTW, strangely with all the windows down the whine is barely there. I would have thought that it would be louder.

 

Most likely a pinion bearing or worn ring/pinion assembly.

 

Really? That's hard to believe. There has to be a fill plug, otherwise it would be impossible to fill the diff and or check the fluid level. Now, I want to check mine.

 

Sounds complicated, therefore expensive....?

 

Yes, and Yes.

 

Having looked at my copy of the original Jaguar technical notes on the car of 2003, I notice that there is a centre bearing on the propshaft. This could also fail and then whine, but it's a long shot.

 

windows down.

radio cranked up..

and duck tape on rear passengers mouths...

its a miracle .. I can't here the whining anymore?!

 

I have read your post and given it some thought. I agree with the earlier post which rules out a bearing, and mentions gear whine. A cheap aftermarket (sans plastic bushing) counter-shaft sprocket caused my '91 Katana to whine like (everybody loves) Raymond's wife, which is pretty bad.

 

Hey haggis95

I have exactly the same symptoms which I attempted to describe in this thread, in post #7: https://www.jaguarforums.com/forum/x...bly-6th-67203/

What was the solution to your whine issue?

Now I'm suspecting my rear differential, I'm about to check the oil level and will update soon.