Rear Differential / Pinion Shaft Oil Seal Fluid Leak 2014 Jaguar XF

[MJG50 7]

I've just been checking out the MoT history of a 2014 Jaguar XF at the block. It's first MoT with only 20k came up with an advisory of "Fluid leak, but not excessive rear differential (8.4.1 (a) (i))"

I've had a few XFs over the years but wasn't previously aware of a weakness with these seals. Doing a bit of research reveals they are actually a known fault. I'd imagine the seal must have been replaced as the car has done over 20k since then but it's put me off a bit. I can't imagine that the auction assured check would cover a potentially noisy diff. 

I know I probably sound like a punter who asks has the advisory for brake pads from about 10 years ago been done but I always do a fair bit of research now auctions are online only and just wondered if anyone else has had experience of leaking diff seals on these XFs

[BHM 994]

Probably a Jag dealer looking for some graft at the first MOT. 

[Halfpenny 114]

Known problem. The pinion oil seal is easy to replace with the diff in the car but difficult to get the job spot on. There is a crush sleeve which sets the pinion preload so the position of the pinion nut must be marked so that it is returned to EXACTLY the same spot. Failure to do this will result in wrong bearing preload and possible noisy diff.  To do the job properly the diff should be removed from the car and pre-load set - its sensitive. JLR use a computer-controlled machine to set this dynamically at the factory (so I've been told).

I'm thinking you're a member of the general public rather than motor trade? (apologies if I'm wrong).

Personally not a fan of these cars for a bunch of reasons. If you want something nice for yourself to drive about in without headaches then don't buy a JLR product, maybe go for a Lexus? I'm pretty much through with JLR shite. I read the new French boss is going big on a drive to improve quality - when did we hear that before?

[MJG50 7]

Many thanks for the replies. I'm really impressed with the product knowledge there Halfpenny. I used to specialise in Jags way back in the 90s but these days I'm trying to get back into the trade with run of the mill cars. I'm only part-time now though as high auction prices and annoying punters have really put me off going into the trade in a bigger way again. Maybe it's just me but I've found more recently anything vaguely prestige attracts really annoying timewasters / dreamers, wasting hours and offering £1500 under the asking price.

I have an old customer who wants me to source a late X250 XF as he doesn't fancy the new shape model. I've never had an Ingenium one but I really don't fancy any JLR product with that 2.0 litre 4 cylinder Ingenium engine. It's been proving tricky to find a late X250 XF as they all seem to make an absolute fortune at auction even though they aren't the quickest of sellers. Quite a few I saw go through the block in March are still on the Auto Trader! One even made nearly £2k over CAP Clean this afternoon and the most recent MoT had a lot of brake related advisories.

Going back to the pinion oil seal, I've done some more research now and it does seem quite a common problem. I've never encountered it with any early XFs I've had though. It's come up as an MoT advisory on a few later XFs and XEs I've seen advertised. It sounds an absolute nightmare job to do.

The only positive I can think of is that this advisory was 20k ago and the car is a one owner so he/she didn't get rid of it when this fault occured. I am hoping that it would have been carried out to a high standard so hopefully it hasn't caused a noisy diff. I'm trying to get the warranty history of the car but I no longer have a helpful contact at JLR. 

If the pinion nut isn't put back in the same place would it immediately cause a noisy diff or is it something that would get progressively worse with time? As I say, I'm hoping it's all been sorted. If they made a mess of it when first advised, I doubt the owner would have kept it for years afterwards.  There's no way I'd touch it if the most recent MoT had that as an advisory.

Funnily enough, I used to love a Lexus back in the day, especially an LS430 (undoubtedly the quietest car I've ever driven) although in saying that my last BCA one lit up like a Christmas tree a few yards down the road and cost me £1300 to put out the EML and traction light. My customer isn't keen on anything apart from the Jag XF but I'm with you regarding JLR - I've been very lucky with the occasional Range Rover I had but I wouldn't have the nerve to touch them nowadays. I think that new French boss is probably all talk. Even if I was buying new (which I never have and never will) I wouldn't fancy anything from JLR whereas in the 90s and early 2000s if money was no object and I didn't care about depreciation, I'd have loved a new XJ.

Edited July 10, 2021 by MJG50

[Halfpenny 114]

The bearing preload represents the degree of crush of the crush sleeve. This in turn sets the axial position of the pinion and hence the pinion-crownwheel tooth mesh.  It is this mesh which is crucial to a quiet diff.

In the old days when we were rebuilding a diff we would install a new bearing and crush sleeve and then put engineer's blue on the pinion teeth. Tighten up the pinion nut and look at the blue to gauge the mesh contact pattern. What you are looking for is a elongated oval contact patch in the centre of the teeth. If the contact is too far toward the heel or toe of the tooth then the result is a noisy diff and driveline 'clonk' due to excessive backlash. The whining noise is at the tooth contact frequency and will vary depending on whether the teeth are contacting on the front or rear face (i.e. drive or overrun). Some diffs you could play tunes on with the throttle. A noisy diff on a luxury car just ruins it.

Replacing a pinion oil seal with the diff in the car is tricky because you are undoing the pinion and then when you do it up again hoping its position has not changed. This means trying to get the nut in exactly the same position.  Really you should have the diff off the car, replace the crush sleeve and check tooth mesh...  

AFAIK pinion oil leaks have been a problem on the XFs from start of production. In my opinion its down to poor quality control. JLR suffer from lack of development and poor quality control. Some aspects of their design are just bizarre - for example the use of alloy bolts on the Evoque steering assist unit - yes, they snap!

[Frank Cannon 812]

'Rear axle pre-load' really does come under the heading of witchcraft.....even a lot of good gearbox guys avoid going there. 

 

JLR products are always under cooked, they were when I was doing nothing but, XJ40s and Rangie Classics. Great sellers, poor products. 

Edited July 11, 2021 by Frank Cannon

[MJG50 7]

Many thanks for the detailed replies - if anything it's made me even keener to stick to mainstream stuff in the future. I guess I was quite lucky in the past with Jaguars (apart from one head gasket nightmare). I still can't believe I wasn't aware of that rear diff known problem to be honest, if I knew about it before I'd have been paranoid about the XFs I've bought. Even if I find one that doesn't have a history of that problem, it could happen at anytime. 

Going back to the car in question though, my gut feeling is that the problem was fixed to a decent standard years ago (and main dealer serviced every year since then) so it probably is ok now. I did faff about worrying why a low mileage 2014 XF was in a Pendragon sale recently (I assumed if it was any good they'd sell it themselves), I didn't buy it and I noticed the dealer who bought it sold it pretty quick for about a £2k margin!

I guess it's all a balance between taking a calculated risk and never buy anything! There was a very cheap XF (about £2k below CAP Clean) recently but it had no mechanical report. It was from HR Owen at BCA and I gather they often don't seem to put reports on their cars. I didn't have the nerve to go for it and so far, it hasn't surfaced on Auto Trader/eBay so there may well have been a problem with it.

Again, I didn't know about the alloy bolts on the Evoque! I did once buy a 3 year old ex-lease Citroen C5 though and I immediately noticed the steering wheel felt a bit loose. I drove it gingerly and my mechanic told me that bolt that connects the steering was extremely loose!! When I got the service print-out from the lease company I saw it was advised at the last service but not acted upon! 

Edited July 11, 2021 by MJG50

[MJG50 7]

Thanks again for all the detailed information.

I've finally managed to get hold of the warranty and repair records and there's no sign of anything to do with the diff being repaired at all! It seems strange as literally everything else including brake pads has been carried out at the supplying Jaguar dealer! So either they took it to an independent for the first time or just ignored it and subsequent MoTs haven't noticed it!

I'd have taken a chance on it if it had a whole new diff under warranty but I won't go for it now at all. I bet it will make about £1500 over CAP Clean anyway!

It's a shame about the diff issue with the XF as I've always liked them myself and in the old days it's the sort of thing I'd go for if I wanted a smoker but these days I've totally got interesting cars out of my system and don't mind driving anything that's reliable. 

My customer has been looking into 3.0 litre new shape XFs but I'm not sure that's a good idea, I see they also suffer from the same pinion seal problem, amongst a lot of other stuff. Personally speaking, I much prefer the look of the Mark 1 XF, both inside and outside. To me, the new XF looks pretty bland, a bit Audi like and the interior just feels like any volume car. The leather seems so thin too compared with older models. It's the same with the Sportbrake, the first gen looks pretty smart but I can't take to the new ones at all, the rear almost reminds me of a new Focus Estate! Jaguar have come a long way styling wise since the Series III XJ, in the wrong direction if you ask me!

Edited July 12, 2021 by MJG50