So, I had a Quaife Limited Slip Differential installed by some wonderful friends (and father in law)-here's what was required, how we did it, and what we screwed up.

Parts needed:
Quaife ATB Limited Slip Diff (QDF3W)
An 18mm socket to sacrifice-see below
RTV gasket maker
LM6034049-LM603012 bearing and race x 2 (I used a Timken set)
2 half shaft seals, listed as 2R8W-4B4-16AA, Jag part # XR821244
Gear oil, at least 1L, could need more (we used 90w140 full synthentic, 2L, but we spilled a bunch in the process, so 1L may be enough)

Tools you'll want/need
-Metric sockets
-Snap ring pliers (there's a big, big snap ring)
-Jack, jackstands, chocks (or a lift for preference)
-Air tools are nice, as with most jobs
-Dial indicator to measure backlash
-Torque wrench

I acquired a diff from Racing Green Cars in England, for about 2k after shipping and duties; I believe they are cheaper sources to be found in the US. Jacks Transmissions sells them, although racing green may be faster to deliver. I've also seen a vendor list them through the Sears website.

My excellent father in law (a heavy duty mechanic instructor) Lanny and a wonderful friend of ours, Roger, who is also a mechanic but much more spry agreed to take on the challenge if I could locate the parts.

I purchased a Timken DRW311 diff rebuild kit for the LM603012 bearings and cups. I ordered some 603011 cups, but these were not required; the diff uses the cups in the rebuild kit. The included RTV was nice, and if I need a pinion seal and bearing later, I guess I'm set, but they were not required for this, and I didn't actually check if there were the right size-sorry. You don't need to remove the pinion assembly for this job.

We did need at least one half shaft seal, and I ordered the wrong ones; the Jag part number is XR821244, listed as 2R8W-4B4-16AA on the seal. We damaged the passenger's side seal while removing it, then realized the ones I had ordered wouldn't fit! You might as well order them through Jaguar, as their price ($18) is reasonable and they can find them easily. Fortunately my dealership had one in stock and we salvaged the drivers side seal. Ideally we would have replaced both.

I recommend using a lift if you have access to one. We jacked the car up by the differential, placed jack stands as high as possible, and made do. We started by removing the passenger side rear wheel, brake (parking and disc, which you should then place spacers into), and detached the toe link and upper and lower wishbones. You should then remove the speed sensor line (unlike us) and the shaft should slide right out of the diff. If you screw up and forget to remove the speed sensor line, it may snap like mine did, and then you have to solder it back together-no fun.

We then detached the differential from the drive shaft, marking the alignment with chalk and then removing the lock-nutted bolts. This required putting the car in and out of neutral repeatedly; if you don't have spacers in those brakes, this will delay you later, as you have to hit the brakes to shift the transmission, and the parking brake will try to automatically engage, adjusting itself outwards and requiring a brake tool to reset.

Then the rear differential support bolts had to be removed; there may be a 'special Jaguar part' for this, but we hacked up a 18mm socket for a total final dimension as seen; this still required a pry bar to make a slight dent in the trunk well to fit. This is the most frustrating part of the job; if you can plan this out ahead of time, your day will be hours quicker.

With the back bolts removed, we undid the single 'forward' bolt and then carefully wrestled and carefully maneuvered the diff off of the drivers side half shaft to avoid damaging the seal. Some oil will leak out of the diff as you do this.

With the diff on the workbench (or in a big tub), you can crack the case and get to work. Once the oil is drained, you can check the backlash; we saw about 2 thou.

We destroyed the passenger's side seal while removing it, although some careful folks have saved it; if you can replace them, you should, as this is a lot of work to ignore a cheap seal! Behind this you'll find a big snapring. If you weren't already wearing goggles, put them on and tell your friends to watch out. A faceshield would be a good idea if you have one/enjoy your teeth. Hopefully it is removed without incident, and the diff will now be free on the passengers side.

The bearing cap on the driver's side can now be removed (we found the torque to be quite high-we reinstalled at 85ft-lbs). With the diff out, you can remove the ring gear and get to work on the new diff! We also took the opportunity to clean the casing, especially magnet so we have something to compare to later. Nothing extreme, but we want to have a clean baseline to compare against if we ever open it again.

We washed the new diff with varsol before installing, as it was packed in grease. We then tapped on the new bearings (which we should have used a press or at least a brass hammer for, but you work with what you have in front of you) and attached the ring gear. The snap ring needed some taps to get reseated properly-make sure it's in there right. After reinstalling the new diff, we checked the backlash, and seemingly like everyone else who has done these, found that it hadn't changed.

We made a new gasket with the kit provided RTV and sealed the unit up again. The new seal was installed on the passenger's side (and one old seal remained on the driver's side), and then we had to wrestle the diff back into place. We used a jack to do this; if you're on a lift, you can probably manhandle it a lot better. After carefully getting the driver's side halfshaft installed (try lifting the wheel up to line it up correctly), the back bolts seemed easier to line up first, rather than the vertical fron bolt. Once a few points are lined up, you 'just' have to reverse the installation-driveshaft, axle, brakes, etc.

Filling the diff-we tried to add fluid first, but we then leaked it all out while wrestling it back into the car. While it is in the car, the fill hole requires a hose to reach; use the widest one you can fit, as the oil is viscous and the diff holds a surprising amount. We found holding the bottle in the wheelwell was the best location.

Once the car was buttoned up, proceed to drive it like you stole it. I'm loving the traction improvement; I can finally put power down in a corner!

PS-if anyone has more questions or needs higher res photos, please don't hesitate to ask.

 

Enjoy your diff

A little clarification .. you (or they) managed to wiggle the diff out the passenger side without undoing the driver side suspension links? Nice trick

 

Wow.

As a non-XJer, which XJ (year, engine, etc)? Which diff did it have already?

 

The same one that's in your STR

 

Not sure leaving it in was worth it, but yes. The diff is awkward to align, having the other side out too would have been easier on reinstall.

 

2004 XJR, with the stock open diff and the 4.2 L supercharged V8 fed through the 6 speed ZF transmission.

 

If you screw up and forget to remove the speed sensor line, it may snap like mine did, and then you have to solder it back together-no fun.

For the record-this has reared it's head as an engine light; currently my mechanic is ordering a new rear wiring harness to try and fix this. Ouch-don't make my mistake!!