This weekend I changed the differential fluid on my wife’s new-to-us 2001 XKR. From reading on the forums and watching a couple of YouTube videos it seems that this is a feared maintenance event as there is no drain plug, you can’t remove the diff cover (without removing the diff) and the fill plug isn’t easily accessible. Some have reported drilling holes in their trunks as access ports, others have reported needing to make special tools to get at the fill plug.
I didn’t find any heroics to be necessary. I do have a half-height lift in my garage (which does make any work under the car easier), but that wouldn’t be required at all.
I just needed the right combination of extensions to get the diff fill plug out. I then just used a hand pump to get the fluid out and then I used the same pump to get the new fluid back in. The video below on my YouTube channel (the worst channel on YouTube) shows what I did roughly.
Measuring the fluid coming out is important to make sure you get as close to all of it as possible. In the end I got almost all of the fluid out.
Really this isn’t a big deal to do. I used Valvoline Synthetic 75W-140 gear oil since I have read that fluid was close in viscosity to the original stuff. I would say it was probably fairly close. Maybe a bit thinner, but when you factor in the fact that old fluid was old, it’s probably about correct.
This should apply to the XK8, XJ8, and XJR as well, with the caveat that some of the access to the fill plug might be different.
Link to the video below: