Does anyone know if the rear differential on a 2008 XJ8 has a breather plug somewhere. At only 66K Kilometers = 40K miles, my left side differential seal just started leaking oil. Not dripping but coming out at speed. I know that pre 2004 XJ's have a breather plug on top of the differential that sometimes would get plugged thus causing excess pressure in the differential causing the oil to pressure out, once cleaned all was ok.

If it is the seal, I can replace that, but I know another member (Penguin under the post "Grooved inner shaft Axle drive shaft diameter") talked about how he had a deep scratch in the half axle that goes into the differential where the seal is and thus will need to get a new axle or shaft sleeve but he has recevied no advise here. We need a Jaguar mechanic who can shed some light here that would be greatly appreciated .

Another interesting factor is that the car was in Kentucky for its first four years of ownership, a state where the wheather is not to warm and not to cold. Here in Wisconsin after only driving the car for 2K miles the weather just started to turn cold about 30F and now the seal is leaking and two bushings have leaked out their oil. I have heard that Jaguars don't like chilly weather and I think this proves that one!

Want to tackle this job this weekend but want to do it right the first time and only do what is necessary.

LCMJAGUAR
2008 XJ8 VDP
1988 XJ6

 

Maybe you need a speedi-sleeve here:
http://www.skf.com/files/344136.pdf

 

I am not familiar with the Jag dif, but just generally speaking, all difs have to have a vent. I don't see it in the service manual, but there has to be one. If it is plugged, that can definitely account for a leak, and opening the vent could fix the problem. Without a vent the oil expansion from the heat while driving can build up considerable pressure.

I don't believe the seal surface of the axle yokes could have a scratch, unless it was done by a mechanic. Even a small nick in the seal surface from the factory would result in a leak in short order. It is much more likely that a mechanic gouged the surface when he removed the yoke and tried to pin it on a manufacturing flaw. It is likely, however, that after many driving miles, there is a groove worn where the seal contacts the sealing surface of the yoke. That is normal wear. It can be cleaned up by polishing, or if severe, a sleeve like mentioned can be installed to cover the groove...only about $20.

Sorry I'm not familiar with the particulars of the XJ8 dif...I have worked on many other rear ends, though.

John

 

Ironically my 07 had this issue exactly one year ago. At the time, it was the same age and miles as yours. Still under warranty so the dealer replaced the seal. The leak came back a few weeks later and the dealer replaced the diff. Not sure if cold weather was a factor but it happened just as the cold winter temps took hold here in Connecticut.

While in the dealer's care the front passenger airbag (suspension system) failed so the dealer replaced that too. Frigid temps seem to be no friend of the these cars.