There is what I believe to be excess play when I push in at the 12:00 position on the left rear wheel with the car on the lift. The right side has some slight play too, but not as much.

I had a friend push the wheel in and out at the 12:00 position while I investigated what was moving. I thought maybe bearings or the U joints in the short shaft. But those items are solid.

The movement is coming from the short shaft itself moving in and out of the differential. How much movement is normal, what does it mean if it’s excessive, and how is it adjusted or repaired? It appears that the shaft itself controls the camber, so there must be some shims in the differential housing?

Any advice is appreciated!!

 

There shouldn’t be any real movement from the short hub coming out of the diff. Likely a bearing is coming apart.

 

I was afraid of something like that. About the only thing I haven't touched during my refurbishing process over the years is the rear subframe and differential. I did replace the rear wheel bearings, brakes, shocks, and the differential oil, but that was it as far as the rear end.

I think the problem is a bearing inside the differential housing that controls the end play of the half shaft. The movement is DEFINITELY inside the differential, and not in the wheel bearings nor in the half shaft U joints. I'm trying to narrow down the parts that I'll need to replace.

Here is a link to what I think is the parts diagram in question here:

Xj 1998 - 2003 (from 812317 To F59525) (x308) Classic / Differential Assembly | Jaguar Land Rover Classic Parts

I'm not sure what I'm looking at but it would be part #13 that is moving in and out if I'm correct. So that might mean bearing #17 is bad?. Can anyone confirm which part number(s) are likely causing the issue? I see that many of the parts are NLA, but having the part numbers always helps. Any additional advice is greatly appreciated! Thank you.

 

If you're sure your U joints are tight then it's most likely the diff output stub bearing is worn. You'll also need a new collet and potentially a new snap ring.
The original custom bearings are NLA but SNG Barratt has a replacement kit (different bearing with spacers) if I remember right.
Can't check the part number now, I'll check when I get home. I also might have a couple used output shaft assemblies lying around that may be good, if you're interested...

 

Circling back to this project. I found a used differential with low miles, and I am going to swap it with mine. I will keep my original differential and someday I'll dig into repairing it, but that's a thread for another day!

I had the car up on the lift when I was diagnosing the problem, and I made a good effort to identify all the subframe bushings with the help of the Jag classic parts website, and I ordered replacements. I may have missed something, but I laid out the parts when I received them and looked up at it and I think I can see where everything will go when I get that far. I ordered new shocks and the pads/cup things that the springs push against.

Here are some observations and questions before I get going:

1. I plan to mark the eccentric bolts that hold the wheel hubs on so I can put them back in the same spot for the alignment. Are there other alignment points to watch for?

2. After I remove the hubs, it looks like I can take the short shafts off at the differential and disconnect the driveshaft. Are there any timing or clocking concerns with any of that like there is with CV joints? It doesn't look like there would be, but I don't want to put it back together and have a shaft bind.

3. Any advice on actually removing the old differential and reinstalling the "new" one? I will have a helper and we're both at least somewhat mechanically inclined so I'm sure we'll figure it out. I know it's very heavy so we'll have to come up with a way to handle it.

4. I plan to drain the oil out of the "new" one and fill it before I install it. Any reason that's a bad idea?

5. I plan to use a floor jack under the springs to hold them, then slowly let it down to relieve the tension. Bad idea? Should I get spring compressors?

6. Anything else I should be asking?

Thank you in advance!

 

hubs don’t have to come out just unbolt the 11/16 nuts on the half shaft flange and it tilts away

springs fall out nice and easy when the sub comes down no risk

 

I think I’m learning more as I look at it. Does the whole subframe, differential and all, come down out of the car? Say maybe with a transmission jack or something?

Edit: I think the light bulb finally came on! I see how it works now. I was struggling with how to access the upper shock nuts but I see now that it will all just come down together. Actually not a big deal. I think I’ll use a scissor cart to let the subframe down. I kept thinking I had to take it out piece by piece.

Sorry for my temporary ignorance!

 

What is this for? Anything I need to be concerned about when installing the new differential?

 

Count the number of threads that hub assembly comes out. Put everything back the same way and it’ll be fine.

 

While I'm swapping the differential, I'm replacing one of the short shafts due to pretty significant thread damage from some point in the car's life. I noticed it when I had the hubs off several years ago to install new rear wheel bearings, but the nut went back on and it torqued up fine, so I left it at that. It's been fine ever since, but I made a mental note that if I'm ever working on the rear end again I'll fix it. So I got a used short shaft in good shape with the differential for this purpose.

Anyway, take a look at the axle nut in this picture. I do not remember the axle nut having a helicoil looking thing inside it when I did the wheel bearings. However, the "new" (used) shaft has one (see pic), and I took the nut off the car to check, and it has one too. I'm not sure what I'm seeing. It's either a massive coincidence that two axle nuts needed helicoils, or it's a normal thing and I'm simply ignorant.

Does anyone know anything about this? What purpose does this serve? It appears that the helicoil goes about 3/4 of the way through the threads in the nuts. I just think it's odd, and wondering if it's normal or what purpose it serves.

Another question I have: I'm not going to touch the alignment bolts on the subframe when I lower it down, but do you think I should get the car aligned anyway? I suppose the subframe may not bolt back up exactly the same as it comes out, which could affect alignment?

 

I believe that's the deforming thread that stops the nut coming use & makes it's a single use item.

There was a thread a few months ago about rear wheel bearings that went into it & that's where I picked the info up from.

 

Fair enough, thank you. Any idea which way it is supposed to thread on? The deforming threads start at one end of the nut and run about 3/4 of the way through, so there is an area of threads inside the nut that doesn't really do anything. In other words, from one side of the nut you can slide the nut on the shaft a few millimeters before it hits the deforming threads. From the other side of the nut, the deforming threads immediately engage with the threads on the shaft. Wondering if it matters?

Apparently when I did the wheel bearings several years ago I was blissfully ignorant of this deforming thread thing and just torqued the nuts in place. If I did it right, it's because I got lucky. That, or it doesn't matter which way they thread on.

 

The nuts are a ONE TIME USE.

If you must reuse, I would suggest LOC-TITE.

 

Thank you, I suspected they were single use from Hooli's comment as well, so I went ahead and ordered two of them.

The workshop manual (see picture), says that I should put loctite 270 (which is the red permanent stuff) on the splines and thread? Are they serious? What if you EVER had to replace the wheel bearings again?? They must be referring to something else? I have NO intention of doing that. Is that bad? I can see maybe the threads if I was to reuse the nut, but the splines too?? I was going to rub some grease on the splines til I read this.

 

No idea sorry, I've never had to do the job on a x308.

 

red loctite is not that big of a deal a crappy propane torch solves that problem easy. either way you don’t need it

 

What is the huge washer/spacer thing for? There are two of them (only one pictured). At first I was convinced it had something to do with alignment adjustments, which is why I marked it like this, but I no longer believe that because when I removed the bolts, there was no adjustment anyplace. I can't really see what it does other than a spacer, but why not just use a shorter bolt? I really don't see anything helpful in the workshop manual, but it's probably called something unfamiliar to me and I'm not looking in the right chapter. If anyone knows, I'd appreciate an education!

 

I figured out the spacers mentioned in the prior post, and how all of that works for the wishbones.

Got this project completed. The new (salvage) differential is installed and everything works great! Below are some pictures. I took the cover off the “new” differential, cleaned the surfaces, and put a thin layer of sealer on to make sure it wouldn’t leak. Installed new shocks while I was at it, and new foam donuts. Also installed new large bushings at the front corners of the subframe. I forgot to take a picture of the wishbones and hubs, and the reinstalled subframe, but it went together nicely.

The hydraulic lift cart was the key to the whole thing. I removed the subframe myself and did most of the reassembly, then had help getting the complete subframe back up into the car. I MIGHT have gotten it myself, but it was easier with two people. One to guide/watch the lifting process, and the other to jack up the lift. The new differential has virtually no in/out play at the half shafts and it seems to be in good shape. Hopefully it will last me a long time, especially since the car is driven gently in semi-retirement!

Here are two “before” pictures when I first let the subframe down from the car:





And here are a few pictures of the salvage differential and reassembly process:









For some reason I forgot to take "after" pictures, so this is it I guess. After this picture, the wishbones, shocks, and springs were added before putting it up in the car.