Hello Everyone,

I just joined!

I have a 2003 XJR, (Anthracite/ black interior) which has been my favorite toy now for about eight years. People ask how it has been owning a Jag, and I tell them every day I get in it, it is like Christmas morning.

She has 134k on her, and have not had to do too much. Last year I did have to replace the throttle body, which really wasn't bad. I bought a remanned unit from ASI in Tennessee. So far, so good.

The reason I am writing is I noticed some drips from the rear end of the vehicle. So I crawled under it last evening and noticed it is definitely leaking. I understand there is a vent on these that can get clogged up. Can someone help me with this? I can't see it, but then there is so much structure under there, I can't see much. Also, I thought I would replace the differential fluid, (if the seal is not bad), but while I see the drain plug, I do not see any fill plug - something that might be useful once I drain it. . Also, is it likely/possible the seal is bad? Some information would be greatly appreciated. Thanks!

Vehicles:
2003 XJR
1991 BMW 325i convertible
2012 GMC Terrain - hers
1966 Pontiac LeMans Convertible

 

The breather is located on the RH side of the differential rear cover. The fill plug is to the left also on the back cover.

Use the search function of the X308 forum as this subject has been discussed many times, so you can find very useful information.

 

I believe the diagram and photo below are of the same differential that is in your car. The breather is number 3 on the diagram, and the breather is clearly visible in the photo as well.

I wrenched mine off about 6 months ago and cleaned it out with carb cleaner and my air compressor. My differential did not and does not leak, and the breather did not appear to be clogged, but it made me feel better to take it out and clean it. I was changing the fluid anyway, so I was already under there.

I hope this helps.

 

I have written and exhausted this problem years ago. PLUMS and I went back and forth with the issue and some people remove and clean while others simply replace the vent assy.

I wrote up a customer complaint scenario describing my adventure with replacing the seal only to find out the the vent was blocked and the seal replacement did NOTHING to stop the leak. After replacing the vent assy, the diff no longer leaked.

I recommend checking the vent before blindly replacing seals.

bob

 

I agree with Bob on the vent. One thing I have also learned with these X308 diffs is that the oil travels thru the splines of the pinion and stub axle and travel from under the axle nut. I have taken them off several X308 diffs and thoroughly cleaned them off only to discover what appears is the pinion splines seem very weak and wear easily.

 

This TSB is for the X400 but the principle is the same.

bob

 

Thanks to all of you for your help. The picture was particularly helpful along with the note about taking it off to clean it. I did not know it could be taken off. One other note, I do not see the fill plug on the left side, in the picture, but will look for it on mine.
I will also try to find some of the other threads on this subject for additional information.

Thanks again everyone. I appreciate it.

 

The fill plug is definitely there. You just have to have eyes
on the ends of your fingers.

 

The level/fill plug is on the RIGHT side of the rear cover below the diff vent.

There are posts that have pics of people drilling large holes in the spare wheel well for access to the level/fill plug.

bob

 

I did a oil change on a XJR a while back. A short 1/2" wobble extension and 1/2" breaker bar to start, then a piece of square stock and a ratcheting wrench from the side to remove the plug.

But this method didn't work on my XK8. Not enough clearance for the wobble extension, so I cut the hole in the spare tire well as Bob mentioned.

 

Thanks to Plums for the humo"u"r, and thanks to Motorcarman for the additional info. I saw the plug below the vent originally when I looked at the differential, but I thought that was the drain plug since it is so low. Now I guess I need to know where the drain plug is, because the one below the vent is the only one I can see. I will look at some older posts and see what those pictures show. Thanks again.

 

Jaguar eliminated the drain plug with the X308!!!!!!!!!!!!!
A vacuum can be used to suck out the old fluid and then top it back up.

bob

 

Seriously? I was thinking I had to be missing something somewhere because I could only find one plug! I expected it to be somewhere near the top of the cover, or the housing itself.
It doesn't look like from where that plug is that it would still hold 1.8 quarts, but it must. Thank you VERY much for that piece of information. (I can see why some might want to access the plug from the trunk but I will try to use the other method. I will just be patient.

I bought the Royal Purple Max Gear 75 - 140W synthetic lubricant. Based on the info I read, it should be good. (Much more expensive than the Valvoline synthetic 75-90w.) I have cleaned the valve pretty good. It seems to be operating correctly. I also bought a pump. I will try pumping it out, as I don't have a vacuum: unless you have a suggestion for that.

Thanks again, I really appreciate that important piece of information.

 

I used a hand pump. Snaking the hose down is not difficult.

 

 

How much should I buy to drain & fill, thanks.

 

Hi KC, two Quarts will be enough but if you are skillful enough to get all of the old fluid out you'll use almost every drop of that 2 quarts. I was a bit clumsy and spilled a little of the new fluid the last time I changed my differential fluid; came up a tiny bit short and had to "improvise".