I have an 02' x-type 3.0. How often should i have the differential oil changed. It has never been done.

 

jagm1979, if you look at the Jaguar recommended maintenance, they say it is "sealed for life - no maintenance is required". With that being said, I will throw the flag on that. As long as you are not hot rodding the car and driving at 100+ mph all the time, changing the fluid back there can be done every 100K miles without any negative effects. Some may go as short as 60K miles. The big thing is not overheating the rear differential. As long as it is not getting overly hot, you could probably get away with never changing the fluid. But, why risk it when the fluid is fairly cheap and replacing it is fairly easy (just need a vacuum pump to suck the old fluid out).

If you are talking about the transfer case, then I would say to do that every 30K miles. This is another "filled for life" item. But, as many of the members will attest to (me being one of them), the transfer case has very little fluid in it (only 600ml) and any sort of leakage will result in a loss of fluid in no time. Not to mention that the transfer case sees much worse conditions than the rear differential (hot conditions from the motor, more load creating more friction heating, less fluid so it remains hotter since not as much fluid is in contact with the casing to cool it).

The fluid that you need is "full synthetic 75W-140 gear lube".

If you have any questions, ask. Someone will give you all the information that you need.

 

Thanks, the thing is that i took it somewhere and they were charging me $400 to change the fluid in both the transfer case and the rear differential. It seemed really high so i decided to ask around first.

 

Jagm1979, that is a bit high. The big thing that I would ask them though is how they plan on refilling the transfer case. See what they say. The little known fact is that you can not access the fill plug with the transfer case still installed in the car. So, that leads to the question of "how do you put the fluid in the car?" We have come up with 2 other ways (other than dropping the transfer case). The one requires a little bit of fabrication on your part and it essentially amounts to installing a valve in the drain hole (whether it be a check valve or a radiator drain valve). The other method involves jacking up the driver's side of the car so the frame is about 24 inches off of the ground. The jacking method has the car leaning pretty good, but that makes for enough room inside the transfer case to get the full complement of fluid into the transfer case without having to somehow plug the hole with a finger and then slide it out of the way as you quickly put the plug back in. As you will discover, there isn't a lot of room there.

When it comes to fluids, you can plan on spending about $40 in fluid (2 quart bottles of gear lube). If you go the radiator drain valve, that is another $10 in parts. The check valve bit, I can not give you a good price on that.