I tried to google an answer, but could not find anything - the user's manual is utterly useless anyway (probably because they falsely advertised the oil in there "for life"...
X-Type, 2.5L. 2004, AWD
What kind of rear differential is in there? Is it limited slip? If not, what is it?
Which diff oil would I put in there?
I would go for 80W-140 (even if it would normally ask for 75W-140, due to the hotter climate in Australia, and the shops here realized that 75W-140 is simply not required in Australia, which makes it rare and expensive).
So 80W-140 full synthetic I would use.
But I am confused with "hypoid oil" and "limited slip oil" - I do not know, if I need one or the other, or if those 2 are even the same.
Is there any spec the diff oil needs to have?
Would all X-Type use the same diff oil (I would be interested in knowing what to use for 2.1L FWD and 2.5L AWD)

 

Peter, you have a bird of a different feather there. You can have 1 of 2 transfer cases. So, you have to find out when your car was built. If you do not know that date, then simply look in the driver's door jam and you will find it there. If the build date is March 2004 or before (yes, you may have say Nov. 2003 for a 2004 car), then you have the older viscous coupled transfer case. If you have April 2004 or later, then you have the open differential transfer case. In either case, the commended oil was the full synthetic 75W-140 oil. Honestly, if you use full synthetic 80W-90, the 80W-140 (if it is full synthetic), they are all going to be fairly close. The big thing is making sure that it is full synthetic to ensure it will not break down to easily under the stresses that it sees.

As for the limited slip oils. These are really only used for rear end limited slip diffrentials. You may also hear it called a "friction modifier". In short, with limited slip differentials, if the wheels are spinning at the same speed (or fairly close), the plates in the clutch of the limited slip are apart and allows the wheels to spin at different speeds. As the speed difference becomes larger, the clutch engages and "locks" the wheels together to help slow down the faster wheel and speed up the slower wheel. This normally helps improve traction unless an excessive amount of power is being applied, at which point, both tires are going to spin freely at the same speed due to the limited slip. This is normally an additive that has to be added for axles with a limited slip differential. Friction modifiers are somewhat specific to the type of device that you have in the differential. Kinda like you shouldn't use chevy friction modifier in a Ford limited slip unit. Would it work. More than likely. Will it work the way it should? That is more questionable.

When looking at a viscous coupled transfer case, in short, it is using the stickiness of the oil to minimize the amount of slip between the two shafts. As you get more slip, it transfers more power to the slower shaft. This allows for a wheel speed difference for say cornering. But ,this slip also puts heat into the fluid, making it loose its lubricating qualities and not provide as much power transfer. i can go on longer about the pros and cons of the two types of transfer cases. If you want to know, let me know.

As for your question relating to the 2.1L FWD and the 2.5 AWD, the 2 cars are going to use different fluids as the 2.1 FWD does not have a differential. It is powered straight from the transmission and that uses a much thinner tranny fluid. Where, the transfer case and the rear differential on a 2.5 AWD car are going to use the 75W-140 full synthetic fluid. The transmission of the 2.1L and 2.5L will use the same fluid. But, like I said earlier, it is going to be a different fluid than that in the transfer case and rear differential.

 

Hi Thermo, thanks for the detailed reply. Actually probably more detailed than I need it at the moment:
The previous owner just did a fluid change in the transfer case. I am not touching this now.
At the moment I really only want to change the fluid in the REAR differential (rear axle)...
And I am confused by the products on the market: Even after I decide to go for 80W-140 full synthetic, there seem to be still various options.
One has the addition "limited slip", I think another one had the addition "hypoid".

I would like to think that Penrite 80W-140 full synthetic would be good, but it is quite expensive.
The Gulf and Western full synthetic Ultra clear gear oil LS (LS is probably limited slip again) is significantly cheaper... - but I do not know, if I can use this...

 

Hi Thermo,
I found an answer from you from 2014: So the rear axle/differential is not limited slip:
https://www.jaguarforums.com/forum/x...ential-109308/

Now does that just mean that there is no need to use Gulf and Western full synthetic Ultra clear gear oil LS (limited slip) oil, but I can use it anyway - or does it mean that I cannot use this oil?

PS: I just realized that you would not know "Gulf and Western" oils, as that are made in Australia - thus here is what they write regarding their full synthetic 80W-140 oil:

ULTRA CLEAR LS 80W-140 is fully synthetic friction modified, extreme pressure Gear Oil formulated with poly alpha olefin base oil technology. It will provide superior protection, thermal stability and superior EP properties to that of a mineral oil. It is suitable for a wide range of manual transmission, gear boxes and final drives calling for 80W-140 gear oils. Suitable for use in limited slip differentials.

So, does that seem to be suitable for rear axle transmission in my X-Type?

About the built date: I have an "approval plate" with 08/04, but a built date of 01/04. What is the VIN number, where the other transfer box is being introduced?

Update: We do have a shop here in Australia (and NZ), called "Supercheap", and they have a great online service: When I enter my number-plate, it recognizes my car, and it tells me, which product is suitable for my car. It tells me in both cases (Penrite full syn, 80W-140 and Gulf & Western full syn. LS 80W-140) they they are suitable for BOTH "applications:
1. Differential Oil, rear, 1.15L capacity
2. Transfer Case Oil: 0.6L capacity

Well, that sounds good to me...

Another PS: Now I saw several comments on the net that Gulf & Western is probably a low quality oil. Hence, I will probably stick with Penrite.

 

Peter, when I bought my first X type new in 2005, determined to maintain it myself from the start, I checked with my dealer what the various fluids should be. Castrol supplied all oils and fluids to Jaguar at that time and for the rear differential (Open type, not limited) the fluid supplied by Jaguar was Castrol Syntrax Limited Slip 75W-140 Fully Synthetic Gearbox Oil, for which they wanted to charge £50/litre! It was available on the open market for about £12 back then. That oil has since been superseded by Castrol Transmax Limited Slip Long LIfe 75W-140 Fully Synthetic Hypoid Gear Oil, currently £24/litre and that is what I still use.

So limited slip oil for a non limited-slip diff was specified.

Same fluid was specified for all transfer boxes. Of course the earlier viscous coupling type is a version of a limited slip differential, but the VC is a sealed unit within the transfer box, having its own special viscous fluid that really is for the life of the VC itself! It never 'sees' the lubricating oil that plays no part in its limited slip performance. The non VC boxes are open differentials.

 

Thanks astromorg,
Based upon your info (Castrol Transmax Limited Slip Long LIfe 75W-140 Fully Synthetic Hypoid Gear Oil) I found that this specific oil is not only ridiculously expensive here in Australia, but that price then needs to be multiplied by three due to postage costs from overseas, as it does not exist in Australia. BUT I found your recommendation nevertheless quite useful, because if I combine it with what I wrote above, namely that due to the hot climate in Australia 75W-140 does not make much sense and Australia uses 80W-140 instead, I find:
Castrol Syntrax Limited Slip Diff Oil 80W-140
This one is still expensive, but as this is being sold in Australia in the automotive shop 2km away, there are no postage costs. Plus, it is there currently on 20% off special (AU$31.20/L).
Also: While I still do not know, which rear diff oil SPECIFICATION Jaguar recommends for the X-Type, I know (and I wrote this back then in a thread in the S-Type section) :
"At least the Jaguar S-Type workshop manual gives us a bit of a hint this time as to which kind of oil belongs in there:
Ford Spec M2C192A synthetic, which would be a SAE 75W140 grade hypoid gear oil (synthetic)."

And "Castrol Syntrax Limited Slip Diff Oil 80W-140" complies with Ford Spec ESZ-M2C190A. And I believe that the difference of 192 to 190 is due to 75W vs. 80W.
Plus, this Castrol says: "It may be used in both limited slip and non limited slip applications", (which confirms what astromorg wrote above).

But now I look again closer at "Penrite Pro Gear 80W-140 full synthetic":
It says on the back (amongst other things):
"May also be used where 75W-140 is required." (Mind you that this is possibly true only for Australia).
"For use in both hypoid and limited slip type differentials."
"Ford M2C-190A"
And this diff oil costs currently in the same automotive shop (repco), also on 20% off: AU$67.20/2.5L (=AU$26.88/L)

IN SUMMARY / CONCLUSION:
Initially I had no hint, which diff oil is specified for the X-Type. With astromorg's hint, I deducted that "Castrol Syntrax Limited Slip Diff Oil 80W-140" is also suitable (at least in Australia), and knowing that, I came to the conclusion that "Penrite Pro Gear 80W-140 full synthetic" is the same, yet a tad cheaper. So I will go for that.

 

https://www.royalpurple.com.au/store...ear-sae-75w-90

 

...while I think, royal purple may also be a good brand, you can see on your link already that it is super-expensive in Australia.
Also, and quite important: Your link is for the wrong fluid. I would not go for 75W-90, when 75W-140 is specified.
Royal purple is also available in 85W-140 - I would also not opt for this... - 80W yes, 85W no.

PS: Dell, your list above became visible only now. This list is a good first help for orientation, even though not complete, e.g. in regards of transmission fluid.
But I also want to do a power steering fluid change soon, and this list saves me from searching the net again - it confirms that pwr. steering fluid is Dexron III, and I use for that purpose a multivehicle transmission fluid, which also claims to suit Dexron III. I use this, because I have no other use for it and I have plenty of it, as I trusted the manufacturer's statement, that is can be used ilo. Lifeguard VI (as ATF for S-Type ZF transmission 6hp26), which is simply not true.)

 

Peter, it's clear you haven't found this document before! Essential to you at this (or any!) time

http://www.jagrepair.com/images/Auto...s-09-2009-.pdf

Transmission is covered near the end of it

The parent site, JagRepair at JagRepair.com - Jaguar Repair Information Resource is a good all round Jaguar source

 

Hi astromorg,
Indeed! I have never seen this document before - neither the Jagrepair site.
Thanks for that. Very useful - for all my S and X's and the XJ8.
All the fluids (incl. their capacity), some torques, even wheel alignment data and the drive belt routing in one place.
So far I had to look up each and ever little detail separately on the net...

 

The link was merely a suggested brand =

 

OK, but as I wrote: Royal Purple is really expensive in Australia. And I made my mind up: Penrite 80W-140 full synthetic.
I am just waiting for an even better special - and I might even buy a 20L canister.
I already spotted 20L for AU$395, but I have to pick it up 175km away or pay AU$25 in postage.
Maybe a miracle happens, which will lead me past that shop anyway... - e.g. for the purpose of buying a ninth Jag - one never knows...

PS:
After seriously checking the net over and over again, I found now a really good deal on ebay and I basically pay AU$385 free postage for 20L of full synthetic Penrite 80W-140.
So I ordered that. I will fill this Diff-oil now into all my cars (rear diff., plus transfer box on the two AWD X-Type).