I offered to help a fellow Jag enthusiast save his sanity before he decides to sell his XJR. We are addressing the rear end where he needs new bushings, shocks, and has a bad output shaft bearing.

I have a rear diff from a '99 XK8 laying around which is the same as his 01 XJR with the exception of the companion flange kit (driveshaft to diff housing flange).

The plan is to either swap the output shaft bearing or the companion flange and use the rest of either diff.

XJR diff: 100k, bad output shaft bearing, slight oil residue near pinion bearing. The fluid looked good when flushed 2 years ago but everything else looks ok.

XK8 diff: mileage is unknown, different companion flange, the rear output shafts had slight oil seepage on bottom. It cleaned up well and oil inside looked clean when changed.

So dilema: Use XK8 diff and swap flange (assume easiest) or swap output shaft bearings into XJR diff (more consuming and complex)?

I plan on dropping the whole rear end to tackle this as well as new shocks, and bushings. I've seen the output shaft swap post on XJ40 so would use that as guide but I've never been inside these diffs before.

It is not a daily driver but assuming the diff and other new parts goes together well the plan is to keep the car.

thoughts?

 

The pinion shaft on the XK does NOT have the extension on it for the JURID flange.

I have 'gone the other way' and cut the steel extension for an XK from an XJ and swapped coupling flanges.

I would opt for the output shaft swap but a good-used diff can't be that hard to find from a 'like-vehicle'.

bob

 

I'd be looking for an XJ8/R diff and drop it in - way less work. Dropping the rear sub assembly is the comfortable way of doing the work, and surprisingly simple and quick. I've lowered it on a sturdy trolleyjack then pushed it onto a wooden pallet to sort out, then back onto the trolley up and in.

 

I am aware of the extension. I've compared the two parts diagrams. It looks like removing the nut on the pinion is only thing in way of swapping them over. ---I didn't see any gaskets or rings that I should replace while swapping but maybe your experience can confirm.


I would shoot for another car/diff but I've got this one and it would save him a couple hundred bucks.

 

Ive dropped mine multiple time and can do it with my eyes closed. I have access to lift but likely use jack stands and drop it on ground.

Once out we will clean up all parts, replace carrier bushings, A-frame bushings, swap diff and check K-strut. I'd like to check upper shock bushings but scarred from mine. I had issues with rusted bolts breaking, top nut breaking loose and other headaches.

Any ideas on better bolts/nuts/hardware to attach shock towers to frame I'm all ears.

 

Swapping the pinion oil seal/flange is not as simple as it sounds.

I have never tried to re-use a flange but you might try it.

bob

 

thanks for info. I'm about to go into shop and pull it apart. Re-using the flange SHOULD work and I'm giving 50/50 on new seal. ---I should know better than this----


Worst case, new seal or just core this diff out and find a new one. I know where one is an hour away and can lift with loader and use air tools but all said in done that whole ordeal would take a day. This is one sitting in back of my truck.

 

As long as your careful, you can reuse the pinion seal. One other thing I do to prevent oil from traveling up the splines on the pinion is clean the pinion and flange off and put a little bit of silicone sealant on them. Then you can put the flange on the pinion and have it kinda oozinto the grooves when they slip down on one another. I've solved many a differential leak using that method.

 

The XK8 diff. Everything came off easy but made a big mess with the diff oil. The seal and everything looks good on this end.

Hopefully I'll get the other diff out in the next day or so and start on that.

 

Update:

Got bad diff and rear section off ad out from car.
Swapping the pinions soon.

I melted and eventually air-hammered out the A-frame bushings yesterday. I cleaned the holes out with a wire brush and then put the new sub frame bushings in. I added a little grease around the bushings and they just slid into the frame. I only used a press to push it the final 1/2 inch but could have just used a mallet.

I'm concerned with how easy the new A-frame bushings popped into the frame. I do not know if guy used OEM or some other (Lemforder/Uro) parts but should still fit tighter then that I would assume. Considering next move, wait and seen about new bushings or remove, wipe grease off and apply some RTV silicone and put them back in. I assume the RTV would tighten it up and keep them licked in place.

Any one ever tried this?

 

Are you saying you are going to swap pinion shafts????
You need to swap the crownwheel also (They are a matched pair).

When the pair is sold it is listed as 'Ring & Pinion' (the set).

bob

 

Sorry for confusion, not changing the pinion itself. I am just swapping the flanges. It looks like the oil seal is the same between the two. I was able to peel the oil ring seal (plastic ring thing) off the original with out breaking it. I may just use a small bead of RTV around the outside the oil seal-Flange lip to keep the diff oil from leaking.

Atleast that is the plan.....

Still confused about the A-frame bushings....

 

Does anyone have a detailed list/pic of the bolts, nuts, and washers for the parts around I left mine with a guy to clean up and they were all dumped into one big box so not sure what goes where.

The parts diagrams, manual, and everything else I've tried has very little detail to tell them apart.

 

Which area bolts?

https://www.jaguarclassicparts.com/u...e-carrier-rear

Some of those should list bolt length and thread sizes, there's other sections for the rear wishbones/arms, and diff.

 

Mostly around the pendulum.

the spacers and locking nuts around the wishbone tie also. I made the mistake of taking both of them apart at same time to clean up. I don't have my car here so I can't look under and see. I tried finding a few pics on eBay but none are close enough to see what each washer and nut look like.

i did not see any specs of bolt/nuts but I'll look again.

 

This one shows some of the spacers used in that area... no bolt specs but it gives an idea where some of the more odd-shaped bits go https://www.jaguarclassicparts.com/u...hbone-assembly