As there is minimal angular misalignment we use rubber doughnuts instead of U joints. U joints need to 'wiggle' to live a long life. Straight shots are hard on them. The rollers eat into the caps.

Also per what RePalm said, laurels should translate to the gear lash being too tight which causes noise.

 

I had my car in at the dealer last week to get the diff etc. at the rear looked at to diagnose that noise - thankfully turned out to be a worn wheel bearing, not the diff. I thought I'd ruled out the bearings as I jacked the rear end up and checked for play in the wheels and any resistance or noise when rotating them with the trans in neutral but found nothing, everything seemed fine. Looks like I dodged a bullet, hopefully others here or reading this with similar issues get lucky too.

The only annoying thing was, I asked the dealer to swap the diff oil anyway while they had the car there and initially they agreed, then the excuses started... "this isn't the right oil sir" (it was) and then "the diff must be sealed for life sir, there is no drain plug so we can't change it without removing the diff"... I understand the common method is to remove the fill/level plug on the back casing and use some form of suction to remove the old oil and refill the same way, is that right?

 

Wheel bearings are a PITA to diagnose.

Dealer can't figure out how to change the rear end oil needs better mechanics...

 

TBH the noise didn't sound like any failed wheel bearing I've heard before, they always seem to whine - this was more of a whirr/rumbling sound.
As for the oil, I think they just didn't want to do it and were just making excuses rather than didn't know how. I'll think carefully before using them again.

 

Pah. Sealed for death!

Yes it's commonly sucked out. DIY or use any competent mechanic. Avoid that place!

 

Hi, I'm new to this forum and not particularly mechanical. My 96 XK8 has started to make a rattling noise from the rear of the car when its cruising along with revs between 1300 and 1600. When you press the accelerator the rattle begins and continues until either the transmission changes down or the revs climb to around 2000.
Is this likely to be a differential issue? or (fingers crossed) something less sinister.

Cheers Moff

 

You're accidentally in the wrong forum, this one is for the X150, you're looking for the previous X100 forum.
Maybe a kind Admin will be along to help move your question.

 

David i just changed my diff two weeks ago there's a stack available in the USA however make sure you go the Gen 1 differential for xk100 also any Lincoln LS pre 2003 will bolt straight up

 

Does this apply to a 2012 XK (5 liter, NA)? I have the car at the shop right now and their first thought is differential, followed by driveshaft...am wondering also if there was a recall for this issue...

 

No it's for the 07-09MY. I'm checking more TSB's the tI have

 

First time I've come across this thread. Is this issue something that is imminent, 50/50, or more unlikely to happen for the 07 to 09 4.2l x150?
Would changing diff oil more often help mitigate?

 

Gears, clutches, bearings and seals do wear. Maintaining the system with fluid changes should benefit the system as a whole as fluid breaks down (with oxidation and heat) and there may be foreign (from wear and tear) bits suspended in the fluid.

 

Hard to tell how many have/had the issue.
Certainly enough complaints for a TSB to be written. I’ve still got the howl, and suspect now that the previous owner sold the car to avoid getting it fixed. Got some upcoming road trips, so if it fails or gets too annoying during those trips, I‘ll consider getting it fixed. No amount of fluid changes will stop the wear causing the howl.

 

Or wait until the diff light comes on!!!

 

Hello forum,
After a bit of investigation it seems that my XK started suffering from the same issue as described in this thread.

I would like to replace the differential fluid to determine if it will resolve the issue. Can anyone recommend a suitable differential fluid?

Additionally, are there any known additives that could be beneficial?

Thank you!

 

Any good quality 75W-140 GL5 gear oil will be fine. There are many threads and videos where owners are using an oil which is too thin as Jaguar do not publish the viscosity spec. There is no additive that will make any difference.

The most important thing is to change the diff oil at regular intervals, about the same as the gearbox is about right so less than 75k miles / 120k km.

Richard

 

Thanks for the reply! Do we know how many liters can fit it? 1L wont be enough?

 

The volume is 1.25 litres with a completely dry diff. However, as a little old oil will always be left inside, I would suspect that 1 litre would be just enough even if it leaves the final level a few mm below the level plug. However, ordinary, non-OEM branded, diff oil is not particularly expensive so I would buy 2 litres just to be sure.

Richard

 

Is there a drain plug on the XK 07 diff?

 

There is on my 06 so I would guess that there is on the 07. If not, you need an electric or manual suction pump to suck out the old oil. If you have to do that, 1 litre will probably suffice as there will be a little more oil left in.

Richard