I have not found to much info on the XK/XKR drive train but from some of the posts it has tweaked my interest. All of the jags I have had had a 2 piece drive shaft with an independent rear suspension and a limited slip differential. Also the rear brakes were inboard. I would have thought that as the XJ-s evolved into the XK series there would be improvement to this design. As I understand it they still use a 2 piece drive shaft but I am unsure of what type of rear suspension and do all XK/XKR have limited slip rears. I see it seems all ar running a 3:31 rear gear set which with a 6 speed should be the best of 2 worlds. As a little background which may be sacrilege to some here after a 100K and a burnt valve on my XJ-s I pulled the V-12 and Corvette TPI V8 with a worked 4 speed auto. I used a 1 piece aluminum drive shaft which in my opinion should have been done in the orig. design. Now that I'm older my retrofit days are over but I still enjoy wrenching or programming the newer cars.

 

Limited slip wasn't offered on the XK Series until 2010, and then only on the XKR/RS models. I don't know the driveshaft details...and curious why anyone would even care for that matter. But I can tell you that it works very, very well...and noone seems to be having a problem with there's on this forum

 

From the workshop manual: