Hello!
I have been struggeling to get rid of this really odd noise coming from diff unit. The noise have been present since I bought the vehicle 8 month ago, but have not deteriorated neither disapered. I changed the oil to see if there where any particles in diff oil but it looked ok and I refilled with new. Still left with this load depending gearmesh noise between 80km/h (50mph) and 115kn/h (70mph). The noise where less or not there if I accelerated in sport mode through the speed range at a higher power lets say 1/3 throttle.

Anyway, as a last thing to check before I ordered a new diff, put the aft part of the car on stands and unbolted propellershaft at diff, int bearing and hand brake support bracket to get rubber donut out of the way. The nut holding the diff flange an input shaft is of 32mm size and tested the pre-tension only to find it was loose??!!!!!!! Only thing holding it was the lock funktion as it has a knock down part against the centre!!!
I torqued it up again with lowered ring spanner (did not have a deep socket 32mm). IT DID THE TRICK, NOISE IS GONE!!!!!!!!! For info, I did not have the posibilty to use a torque wrench but used force until it spun on hand brake. Soo, no I can enjoy some pure highway jaguar cruising with out the dodgy noise he he. Feels like I have won the lottery, I realy hope this can help somebody else!!!
Be carfull though when doing work under the car, they are heavy and always use supports. Happy motoring!
/Per

 

It's probably *much* better than the situation that existed before your fortunate discovery.

The torque spec in JTIS is 150-165 NM on a *new* assembly, *however* readers should refer to other commentary here from experienced techs that says otherwise.

On a retorque, Bernard Embry's method of measuring bearing preload might be better. His Jaguar site can be found by searching on the name. Lots of useful info there with a focus on the XJS model.

 

Aha, 150-165Nm. Good to know, Thanks!!!!!

My rough estimation of torque applied would be not more than the stated figure. How would i guess? Well, I have a Ducati which I needed to re-torque the fly-wheel on. That was at 210Nm, and I was very far from that amount of force through the wrench before the hand brake would slip. I mean, if you have a wrench of let's say 350mm, this would give a force of 34kg to reach 150Nm...
No way I could pull more than that laying from underneath the car with one hand he he.

 

A great result!

 

However, if you arrange the wrench just right, brace your shoulders, and push with your leg ...

Or, for the ultimate in force, arrange wrench, let car down on hydraulic jack. However, determining the torque or distance to drop is an exercise left to the implementor. Again ...

 

Lucky man, my experience is that things are always worse than you think!
On an aside - I spent some time long ago at the Land Rover factory and came in one morning to find the assembly line stopped, klaxons going off, people running around like BAFs etc.
It turned out that they'd taken on a new apprentice whose father had taught him always to run nuts onto bolts to keep them matched.
He'd found the entire factory supply of prop shaft bolts and run the Nylock nuts onto them with an air wrench!!

 

Keep that guy away from airplanes, please...
I am going to go underneath my 05 vdp and see what's up with the back end of the driveshaft. Thinking I have a similar problem. Same exact speeds. Perfect tires, smooth as silk at 70-90 mph etc.
Great thread, btw.

 

Hej Per, kul att du lyckades fixa oljudet!

Was the noise anything similar to the one in my video? I have been made to believe it is the output shaft bearings.

[youtube]IcGtv3jmnIM[/youtube]

 

Oh dear! Sorry no, the noise that I had was not present until after 80km/h up to 110km/h. And not by far that load and grinding. In my ears this sounds more like broken ball/roller bearing than gearmesh noise.
Thought, does the noise change when cornering? If it would be the output bearings it should be, as they are taking strain from wheel due to driveshaft working as upper controllarm... Lycka till !
/BR Per

 

No, the noise is constant even while cornering. Everything tells me it should be the diff output bearings though. I'm patiently researching while being unable to drive, due to a spinal surgery I had 10 days ago. 6 weeks without driving

 

One of the non-Jaguar techs, possibly Beav, posted a very nice chart of all the noise characteristics of the different failure modes in rear ends. Not sure of the exact title or url.

 

Especially in your XKR.

Sport Mode --> Pedal to Floor --> Back into Surgery

 

I've been searching a bit for this, but cannot find it. Any more hints? Who is Beav?

Haha, well actually my back is supposed to be a lot stronger than before now that I've got a sixpack of titanium screws and some rods to support it. They were surprised I could even walk at all with the slipped vertebra I had. After repositioning the vertebra and correcting the angle, I came out of surgery 4.5cm taller than before. I don't know if I'll even fit in the XKR anymore with 189.5cm...

 

He is a member. So, in the advanced search panel you can specify your keywords, and limit it to posts by member name.

 

I was hoping that this fix would've sorted my Xk8 as the noise was never there when i first got the car, but while i was waiting for the registration to be sorted i changed the discs and pads, then the the next time i drove the car there was this noise, so i've been all over the brakes again to no avail, so now i've just done the diff nut (eighth of a turn) as described on here but unfortunately no difference,!!!!
(also done the wheel bearings and uj's)
Anything else that could work loose??