Here we are again: Another one of those supposed-to-be "for life" oils: The rear axle / differential oil...
But 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).

Well, I am in Australia, and regarding those 2 options of 75W140, which seem to be the obvious ones: One I can't get at all, and the other one is prohibitively expensive.
So I investigated further, and I think now that it is not without reason that 75W140 is kind of not being offered in Australia: It is warmer in Australia and - where I live it is never below 0 degree Celsius (32 deg Fahrenheit)... and this raises the question: What exactly is viscosity?

VISCOSITY: A fluid with low viscosity flows easily. A fluid with high viscosity tends to resist motion (due to its molecular makeup and internal friction).
A low number stands for a low viscosity, a high number stands for a high viscosity.
Most oils are manufactured to be multigrade oils - our example: 75W 140. The number in front of the W (here 75) defines the viscosity at zero degree Fahrenheit (minus 17.78 degree Celsius). So (see above: lower number = flows easier), this means that a 75W140 oil flows easier at zero degree Fahrenheit than a 80W140 oil. Easy!

And this clearly means: While there are a few areas of Australia, where it could indeed get sometimes below zero degree Celsius, seeing here below -17.78 degree Celsius is definitely somewhere, where most people would never end up. And even if you do get there with a 80W140 oil in the rear axle, the effect would be that (during this very limited time) and only until your axle gets a bit warmer (which would happen quickly), you would use slightly more petrol. So here we have it: 80W140 is definitely perfect for Australia for the S-Type rear axle.

Thus, the oil, which I came up with is Penrite Pro Gear 80W140 FULL SYNTHETIC. I bought 2 x 2.5L for a total of AU$100 (I needed some extra for the other cars). This oil satisfies Ford spec M2C 190A (M2C-190A) (the workshop manual spec was M2C192A (M2C-192A). I believe that the difference between 190 and 192 is the difference between 80 and 75.

So, if Jaguar would specify for the S-Type rear axle Ford spec M2C 190A, this would most certainly make things a lot easier and cheaper for a lot of people...

THUS, finally, I have the right oil, but how do I get the old oil out there (given that due to that nonsensical "for life" philosophy, Jaguar saved the cost for an oil release bolt)? This is what these next pictures are about:


Step one: Remove filler bolt with a 3/8" ratchet (without any socket attached). Better than a ratchet would be a "solid" ratchet, i.e. one without that fragile mechanism. I myself use a ratchet, which got damaged a long time ago and where I welded the mechanism solid. To that ratchet I attach a long pipe to increase the lever-arm. The picture above is actually from when I tightened the filler bolt again, but to open it, you obviously have to turn it anti-clockwise.


I use my fluid pump to get the old fluid out of there. I checked youtube, etc. and some seem to suggest that you can simply poke the suction tube in there and remove the oil...


Thus I tried that, and I even routed the suction pipe around that beam to be able to get the best access.


But I should have known better: This was a pointless exercise, as it is simply not possible to direct that flexible hose inside the axle into the right position. I guess, I got only about 1/3 of the total oil in there out that way. Note: It is always a good idea to fixate the end of the hose with a ring-spanner - and then best place a weight onto that ring-spanner.


I do not have access to a junkyard with old cars and surplus pipes, BUT I had an old surplus TV-antenna here: Perfect. I have cut out that bit, which you see above.


And I fed it into the opening. Very easy.


And now I can direct the end of the pipe very precisely to where I want to have it.


The total amount of oil in the S-Type axle is 1.3L. Above I filled a water bottle for comparison purposes with 1.3L of water and next to it the bottle with the oil I removed from the axle - more than 1.2L. Not bad, I would say. Next I used the pump to fill in the new oil and fitted the filler plug again.


Only after I finished the job, I realized that I could have done one better: To get even the very last bit of oil and dirt out of the rear axle (despite Jaguar's failure to provide a release plug), I could have done, what I have drawn above: Attach my metal pipe (which you have seen in the pictures) to a hose, and that to a solid and air-tight jar as in the sketch and connect the second pipe to an old vacuum cleaner... I'll do that next time.

 

Excellent tutorial!

 

I have done now the diff oil change on my 2.5L X-Type as well, and this time I also made reality out of the sketch above:
I have built that jar, which connects to the vacuum cleaner to get even the very last bit of oil out of the diff... - as much as possible anyway...:

https://www.jaguarforums.com/forum/x...9/#post2682396

 

I posted it before, but can't find it, but I do a similar thing to change the differential fluid in my car, very easy to do. I use a 12" piece of 3/8" copper tubing, bend a 90 degree angle on it with a piece of 4" pipe, both at the hardware store. The 3/8" tubing goes into the flexible plastic tubing of my Harbor Freight fluid pumper, most others are also about the same. There's plenty of room to stick the tubing to the bottom of differential and pump out old stuff. To fill it up again, just reverse the tubing on the pump and pump in the new fluid, I like the Mobil One brand.