My 2014 XJR only has 42K miles and I wanted to service the rear diff.
It's a simple job with a bit of tricky access to the fill plug.



Used a 5/16" Ball Hex but I think it's really a 8mm Allen on the fill plug. I used a short arm Allen wrench to break it loose then my 5/16" Allen socket and ratchet to spin it out.
The same short arm wrench fit the transmission fill plug on my old S Type R. Luckily this plug is not nearly as tight as those darn ZF transmission fill plugs!

The drain plug is a 3/8" square drive. The plug was surprising easy to turn. I put it back with much more torque.




Old oil looked pretty bad and had some real viscous stuff in the pan. I have read about carbon shedding and carbon in the clutch plates. So really black may be normal?
Factory says use Castrol SAF Carbon Mod fluid. I found Redline 75W90 #57904 meets the spec. I have always liked Redline.




Nice magnetic drain plug with some very fine powder on it. Nothing much at all.




Another odd thing is Jaguar wants 2.5 Pts in the rear diff so you don't fill until it overflows the fill port. Can't see why and after the change it was very close to over flowing anyway.
Car feels and drives fine but I had no problems before either. With the look of the factory oil I plan another change in 10K miles or so.
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I just did this 2 weeks ago on my 2012 XJL 5.0 SC with 125k on it. Mine was very dark, more so than yours even. The worst part was cutting down my 8mm to have clearance to remove the fill bolt. I also used Redline 75W90 and for anyone going with Quarts that's 1.25. MIne did not overflow at all. I did let mine drain for 6 hrs starting with warm fluid. My magnet was caked with metal shavings. So far so good with the new lube. In fact I think my rear was switching to one wheel wonder sooner before new lube. Now it can put more power to both wheels under hard acceleration and turning.

Car is new to me so I did a trans flush and filter as well with Redline D6 as well.
Good write up with nice pics!

 

I was hoping someone would post about how the car feels afterward?
Mine seems to put the power down more evenly and I "think" I see less traction control light blinking on hard launches?
Not sure but it has a slightly different feel.
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Mine was changed at the dealer @98k and noticed a small difference in the the diff locking a little faster. However, I never get the traction control light on launches as I am running larger Michelin PS4S tires and they have awesome grip.

 

I have MPS4s as well. Amazing tire. You can nail it and just take off.
To anyone that hasn't done this service around 100k I think its worth it. Your talking less than $30. DIY

 

I run Michelin Pilot Sport 295's on the rear. But I have around 620 HP compared to stock so I can break the tires loose almost anywhere at any speed.
Going 60 mph on dry pavement if I mash the throttle I get a few flashes of the traction control.

Maybe a 305 or 315 tire would help?
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I should mention I also run 295/35R20 rear tires. And I have stock HP.

 

Thread Revival

I'm looking to change my diff fluid again as its been nearly 4 years and 50k miles since the last (first) time I did it. I used Royal Purple 75w90 at the time and I see Club used Redline here. Are there are any new and improved fluids that I haven't heard of?

 

My 2011 XJL now has about 22K on it, with about 8K of that in the last 12 months since I got it.

I don't remember seeing this done in the 10 years of service history.

So I guess the question I have is should I plan to change this sooner due to the age of the original lubricant ? Or am I good for another 30-40K ?

 

Its pretty cheap and easy to do, so I would go for it considering the age.

 

I don't think the 2011 NA engine had the E-Diff?
Pretty sure you have an open rear diff? Still good to change the oil but not as critical if you had the E-Diff.
Also will take a different fluid.
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I finally got another 2 post lift and decided to change the rear diff fluid as I am at 62K miles. Only have 20K miles on the fluid and it looked better than the first time. Still black but with a hint of golden color. Used the same Redline fluid as before.

But I found some worn suspension parts and will be replacing the rear sway bar end links. No grease zerks either so no way to grease them. I went with the Lemforder brand. Not from Jaguar but hopefully a good quality part.





Also the rear Toe links were done as well. Both of these are common wear parts so not unexpected after 10+ years and 62K miles.




Found an odd thing with these small plastic wind deflectors? For some reason 1 out of the 3 rivets holding them on was tore out on both side? No damage to the deflector and a few rivets later it was fixed.




Sure like the new lift and it has some improvements too. The ends now dip down so it's lower to drive over. I also got the double adjustable screw jacks for each arm. This is an extra tall lift with 6' 3" under the arms. So no banging my head on this lift!
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Good looking lift. Arm end supports looks solid. Always remember to check the weight balance when use 2-post lift.
The darkness on read differential oil comes from limited slip clutch plate particles. Its totally normal. They wear on use and because there are no filter all particles stay on oil. Diffs without LS the oil are normally bright even after 100k Miles (+150t km). I have an opinion for oils used on any friction clutch plate/plastic systems, after reduction of mineral components on lubrications and plastics about 2006-2010. After that (and few expensive lessons) i havent used any other than manufacturer recomended lubricants on any systems with plastic-/ teflon-/friction plate components.
The 60t miles are nothing for rear suspension joints itself, but age hit the rubber covers. I changed one toe link for same reason on mine at ~280k km (175k miles) and the joint itself was still tight, but rubber cover broken. Other side stll good. (i check them all twice a year during summer/winter tyre change)
As far as i know the Lemförder (part of ZF group) are OEM supplier for all x351 suspension components, exept shocks. (i quess the front and rear axles are delivered as complete by ZF for the assembly factory?)

Check also the front "banana" arm inner bushes. If you have originals they start to be gone on these miles. The latest ones i got from Lemförder have been lasted much better than early ones. Two first pairs lasted about haft of the pair i have now and they are still good, so there are improvements done somewhere in 2021-2022 on.

 

Yes I found the same thing. The rubber boots all fall apart but no slack or noise in the joints. Plus these parts have not been changed in decades and believe it or not are exactly the same as my old 2003 Lincoln LS! Pretty much from 2000 on they are the same for the Lincoln LS, Jaguar S Type and XJ plus more. Very common parts.

Can you advise any on the lower banana arms? I can grab them and they do rock back and forth a bit. The movement is in the direction of front to rear on the car. Should there be no movement at all?
Car seems to drive and track fine but those are known wear items too. I also read Lemforder was OEM.
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The banana arm inner bushes are an progressive type by rubber having small chambers inside filled with fluid. (thats why its so big in diameter) This is for to spread one direction force for several directions to prevent bang when brakes are slammed hard. Once the chambers inside brokes to each other, so fluid can move freely around, or fluid escape outside the bush come too soft to keep arm position under braking -> This will cause toe out during braking and because bush is soft the wheels start "fishtailing" causing vibration when braking. If you don´t have vibration under braking and/or you don´t see any moist around bushes, they are good.
I did try to compare good and and bad by rocking by hand too last time i changed them, but could not tell the diffrerense. More force is needed than hand (or body weight) to tell. I cut the old bushes to verify that they really had fluid inside.
In fact i read somewhere that new newer propably don´t have fluid but some bit harder gel what don´t escape the chambers so easy. (MB use same construction on some models) Maybe this is the reason why new ones seems to last longer?

 

Clubairth1, the method my mechanic used to determine how badly the bushings on the banana arms were worn was to look at the front to back travel of the wheel when the brakes were abruptly applied while slow rolling the car. Two people job - one to observe. The movement was significant with the bad bushings. Like an inch plus.

 

Thanks for the added tips! The big bushing is all dry and I do on occasion get brake shudder. But a few hard stops usually fixes it so I wrote that off as minor brake pad buildup.
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I am envious of your lift!!

When I did my rear diff fluid, I came a long way from the side and used a fluid transfer pump.

I'm interested to hear how your bushings work out. Mine are busted up and need replaced as well...as soon as I can get this car off the suspension stops and aired back up in the rear.

 

Club, Vasara, I just had the banana arms replaced and I noticed the large diameter bushings are of a green colored rubber. Possibly the new gel that Vasara mentioned. Do you know what color the latest bushings are? I have seen a white colored large bushing as well as the green on these banana arms at my shop.

 

Hi Freddy J
The green part on inner bush are plastic part helping forces to spread larger area of the rubber. Fluid (or gel) are inside of the rubber on small chambers and not visible. I found pics from eBay: Used arm on eBay
No idea about colour coding or reason why different colours. All i have got have had green plastic parts, but seen pics of white ones as well.
Very sorry: When i last time changed the arms i did not compare if there were any difference of the old vs new. Back then i thought they are same, but later i got that new ones have been last much more mileage than previous ones.