If I cruise at around 95-100 km/h and give it some light throttle I get a faint whining noise coming from somewhere in the back. It only seems to happen around that speed interval and it doesn't matter which gear I use. It's been like that since I got the car 2 months ago. Doesn't bother me at all especially since the car is under warranty but wanted to check if anyone knows what to expect.

I'm thinking that it's rear diff related. My dealer checked it out, changed the diff oil which didn't seem to make any difference, and wants to book the car in to continue. Don't know what the dealer's planned next steps are though (try some other stuff or replace parts).

 

they should be able to put it up on a chassis lift, spin the wheels up to 100 km/h, and poke around with a stethoscope. Most likely, the pinion gear or a spider gear needs to be re-shimmed in the differential.

 

We'll see then. For now they told me I can just continue driving the car which I'll do until I book it in again in August or so.

I take it that nothing can go seriously bang even if I drive it pretty hard. A lap or two on the Nürburgring (only about an hour away from home) might happen before I bring it in to the dealer again.

Especially since the car is under warranty I suspect that the dealer will just resort to parts exchange bingo rather than any more intricate repairs. If so, what would they replace - the whole diff?

 

Dealers will replace everythng as long as they're not paying for it!

 

One of the beauties of having warranty. Just curious about what parts will be replaced if they start replacing stuff.

 

Scm is correct. If the gears just need re-shimming, the dealer will replace the entire diff assembly under warranty. Remember, dealers no longer employ mechanics, they employ service technicians more familiar with a computer than a wrench.

 

Yep, I'm very familiar with the dealer parts exchange bingo and a new diff doesn't sound unreasonable then. One of those things that are good to get replaced under warranty I guess, just like the supercharger snout, water pump and coolant system parts...

 

I was at Paramus Jaguar today to access my whining noise. I had their technicians hear the noise I had recorded. We went for a ride and before I could actually get on the road from their lot, he heard the whine and said probably differential is bad. Made appointment for further evaluation and fix. I have an extended warranty so I should be ok. I’ll keep everyone posted.