So I got a used diff to replace the damaged one in my car, naturally the pinion seal is leaking. Not a big deal to replace, if only it was possible to track down a reasonably priced replacement.

Anyone know the SKF or other interchange PN for these seals? It's labeled as a 52x85x9.5 but the actual shaft seal is setback from the back outer surface of the seal, and there's two different diameters on the pinion sleeve. I tried this seal as a replacement (test fit on the pinion of my old diff), but that thicker portion of the pinion sleeve causes issues with friction. Digging around on SKF and Timken product lookup sites, I wasn't able to track it down by dimensions. The usual vendors have them as special order for nearly $100 or more (and one on Ebay for the same price), so I'd really like to avoid that if possible...

 

I don’t have the answer to your question but, I may be able to help you out without a replacement seal.

Remove the pinion nut. If there’s any oil underneath that nut, the seal is likely not the issue. The issue is that the oil travels up the splines of the pinion itself. In my opinion, the metal of the pinion itself is soft and weak. The pinion snub metal is much harder. When torque is applied to the pinion snub itself, in forward and reverse gears, over time the soft splines wear away on the pinion splines. As the years go by and the clearances get larger, more oil can travel in between the pinion and the snub itself. When they leak, the oil typically gets slung from the jurid coupler area.

How I’ve fixed *many* customers cars and my own X308’s without having to replace the pinion seal/snub assembly.

Remove the parking brake “U” shaped bracket that’s under the driveshaft and tuck the cable under the evap pipe under the pinion area.
Completely remove the jurid coupler from the diff and driveshaft but, don’t remove the driveshaft from the car. You can push the driveshaft towards the front of the car but just a little bit and shove a block of wood or some rags at the rear of the of the large single front muffler heat shield to help keep the rear of the driveshaft up and out of the way just a little bit.
Mark the pinion nut, the nose of the pinion and the pinion snub itself with a scribe.
Remove the pinion nut. Deep well 32,34 or 36 mm???? It’s been awhile so please forgive me for not knowing the size.
Place a container under the pinion as oil may come out if the level is high enough.
Remove the pinion snub as carefully as possible so you don’t damage the pinion seal that’s hopefully still in the diff.
Throughly clean the pinion snub splines with brake cleaner and blow it dry with compressed air.
I roll up a rag and place it over the pinion seal then carefully spray brake cleaner on the splines. Blow dry the pinion splines.
On the front of the pinion splines, I use a little bit of silicone rtv all the way around.
On the rear of the pinion snub splines, I apply a little bit of silicone rtv all the way around.
Make sure you have that plastic integrity ring on the back of the snub prior to installing the snub on the pinion splines.
Carefully install the snub onto the pinion splines and slowly push it towards the diff. Make absolutely sure that the lip that goes under the seal inside the diff is properly centered prior to fully seating the snub all the way down to not slice the seal.
The idea is that once you slide the pinion snub down the pinion splines, you’ll effectively fill that air gap that exists between the pinion snub splines and the pinion splines with rtv so it won’t leak.
I have even applied a small amount of rtv on the nose of the pinion just before I install the pinion nut just for extra precaution.
Tighten down the pinion nut and note the position of all 3 scribe marks.
Reinstall the jurid coupler, remove the rags or block of wood supporting the driveshaft from the exhaust heat shield area.
When you go to reinstall the parking brake linkage, be mindful you’ll likely need to readjust that nut so you don’t have an e brake handle that’s too tight or too loose. You get the idea.

*****Top off your differential fluid!!*****

Also make sure the vent on top of the aluminum diff cover is free of any dirt. Compressed air works great on it.

I have never had any issues with leaking come backs or differential failures as long as this is done properly. The output shaft seals, that’s a different repair.

 

There are the seal available on E - bay for the output seals and maybe the input seals

I would personally source from a reputable vendor a high quality bearing like SNK

Question if the seal in question is the same for the earlier X300 as the final wheel bearings from my understanding are different

 

Info we got when I worked at the dealer.

I have done this job a few times.

Let us know if you find an alternative.

 

Now this is an interesting idea. Unfortunately I don't think that it would be the solution on mine, the oil is weeping from the area between the shaft saver flange (metal top hat protecting the seal) and the seal itself... Jurid looked dry when I looked. Also, socket size is deep 32mm - largest size I had in my set.

Parker7 - yes that is the goal (starting with SKF Italy - the most likely OE for the factory part). But to do so (with SKF or other manufacturers), I need an interchange PN! Hopefully SKF will help me out with identifying it.

motorcarman - That's useful info for sure. Looks like the seal replacement isn't too different from how the factory manual describes it, but that PDF gives a (quite high) torque spec for the pinion nut. It's the first bit of information I've seen that gives any kind of info on level of preload required for the 14HU diff pinion.

 

I mark the nut with a punch and use the same nut on re assembly and put it in the same spot.

Also check the diff breather on the top (14mm) and make sure it is not 'stuck-closed' causing pressure buildup.

 

Good advice here about the breather. You should check this first before you dig into replacing the seal. Shortly after I got my XJR, it was leaking around the input shaft seal like you described. After reading a thread on here at the time, I replaced the breather hoping that might be the problem, and it hasn't leaked since. If I remember right, the breather actually contains a one way valve, so it can exhale but not inhale, thus creating a little vacuum inside the differential. My breather was plugged, so I assumed that there was a little pressure buildup in the differential which caused it to seep past the seal. I don't know if I'm remember this correctly about the one way breather, but in any case, replacing the breather solved the leak problem.

 

Motorcarman- yup marking position is the plan for sure, but it's nice to have the torque value in case something goes terribly wrong or I have to mix parts for some reason.

Re breather - pretty sure it's not plugged, when I was working on the diff and tilting it vertical, residual oil would spill out thru the breather. I guess I could swap in the one off my old diff just to see, it looked like it's possible to reach that part with the diff installed in the car

 

The breather was indeed not blocked at all.

I ended up using the 123bearings.com 52x85x8 FKM dual lip seal linked in my original post, and a 99204 speedi-sleeve available from Rockauto or other vendors (99204 is an interchange part number).
It has a tiny bit of flange on it but not nearly as protective as the OEM seal unit. Not sure how I feel about it holding up to heavy rain/road debris, we'll have to see. It is double sealed though... At least it's not leaking oil anymore. The oil in my photos is from me making a mess during R+I, the pinion seal always traps a small pool of oil behind it which will all spill out the moment you pull it... and FKM really does not interact well with brakleen, it gets all crinkly and deformed, so have to be careful about cleaning it up.



Speedi sleeve on the pinion

New seal in place

all put together. Probably room for a 52x85x10 if needed, it opens up more options for off-the-shelf seals

 

Hey there nilanium!
I was wondering how does that replacement seal work? it's been a year since your repair so you should have it road tested already.

I will be doing more or less same rebuild as you did, will use the speedi sleeve and probably 10 thick seal and here is why:
Having an issue with my OE pinion seal and I cant find any identical problem on our forums or anywhere else. I have replaced two OE pinion seals and they die a weird way straight away.
After the first seal change at the shop I quickly discovered a big leak from the pinion and then i was able to pull ryton ring pieces from there, ryton ring got chewed and spit out basically, after I removed the flange and seal I've found ryton ring pieces in between the two parts of the seal. yes we all know that this is a result of bad installation when ryton ring slips off its groove and that is exactly what I thought.
So i took the job myself next time, no flange, no nut, just the OE seal. Followed the TSB, got everything in right: pressed the seal in with the nut, ryton ring and everything in its place, torqued it down, double and triple checked everything,spins and looks alright, breather was fine. And guess what? after a few rides i discover big oil leak once again... I jacked it up today to look at the flange and guess what I discover... the ryton ring in one piece is pushed out of its groove, it left the sealing area and it is just hanging around the flange now. My only thoughts right now are that the seal has an issue with its automatic positioning, flange pushes hard on the seal and the seal instead of being pressed inside the diff casing stays out too far and the ryton ring just jumps out with the pressure... any thoughts?

 

Hi sorry for the late response.

I don't entirely understand the issue.. the seal itself is coming loose from its seat in the diff housing and wrapping around the pinion? I'm confused how it'd even be possible. If there is a buildup in pressure then it means your breather is clogged, so that's almost definitely not the cause of your problem. Plus typically clogged breathers result in oil leaking past seals, not blown seals like your case...

As for my seal, it seems to be holding up fine. I checked before a trip recently and found very low oil level in the diff, but the seal was dry and the only wet area was around the drain plug. I Teflon taped it and went on my way, now that I've put more miles on it since, I'll try and look underneath and maybe check oil level again soon.

 

hey, thanks for the response!
the seal itself is tight in its seat and has no damage, but the ryton ring on the outer diameter is getting pushed out, breather is fine and shouldn't be an issue in this case anyway. so it looks totally fine apart from ryton ring is no longer there and leak is huge. Iam thinking myself that maybe the problem is that those OE seals are not being manufactured for a long time anymore and ones I have used are being just old and materials have aged. I'll be fixing it next month and will make and post pictures.