Changed my rear differential gear oil and thought I'd post my observations.

Car has 56K miles on it and the fluid looked to be original.
Fill plug had about 2mm thickness of sludge on it. No metal shavings thankfully.
Old oil was mostly black (see pic below) and didn't smell burnt or odd.
2003 S-Type V8 uses a gear oil that must meet Ford/Jaguar compatible M2C192A synthetic specification and be 75W-140 in weight.
Capacity is 1.32 L = 1.40 Quart = 45oz.
I was able to pump out about 1.2L and refilled until spilling out which was about the same amount. So I think I've got a good 90% of the fluid changed.

This job is pretty easy to do.
- Get rear of car high enough to slide under
- Use a oil transfer type of pump to draw old oil out
- I suggest a flexible hose w/diameter about 10mm (3/8")
*****I used a butane torch to soften the hose and put a tight bend in it. I bent it at about 125mm (5") from the end which helped a lot in getting it to route straight down. That facilitates pulling oil from the lowest point inside the diff*****
- Reused the same hoses to fill and so I flushed them w/new fluid to most wash the old out before refilling.

 

Hell ya! Im doing this!! Any sure grip sauce needed?

 

Naw our diffs are open. The oil I used already has the friction modifiers in it but it won't any impact on an open diff.

Oh and btw... its $12.50 a bottle at WM. Way cheaper than the Jag or ford branded oil.

Since mine was never changed I'll probably change it again in about 1-2k miles. Just to semi-flush it.

 

Im at 117,000 miles and no idea if its ever been changed before

 

I found a pretty good way to get the old differential fluid out. Instead of just 3/8" hose, if you use a 12" piece of 3/8" copper tubing and put a 75 to 90 degree bend in it and put that inside the hose you can control the bottom of the copper tubing much better than a hose and run it along the bottom and suck almost all the old fluid out with the same hand pump that you use to pump the new fluid in. I like Mobil 1 and use their 75-140 synthetic oil. I called them and was told that it's fine for the S Type Diff. In the old fluid a little glitter is OK, but not too much.Those open diffs can take a lot of punishment and keep working fine..

 

Good suggestion! I'll make one and use it next time. (should work on my other cars too)

 

This guys pretty much sums up how I think about fluid changes.

 

As chance would have it, I am doing the same thing. I have 71, 000 miles on mine now and I have noticed a hum. I initially thought it was a wheel hub going bad and took it to my local garage. They listened to them and they were all quiet and tight, but the rear dif was making some noise. He opened up the one plug and stuck his finger in it and found the gear oil to be low and extremely black, almost like tar.

I was wondering what oil to get and I found this thread. Thank you!


-K

 

I've got about 1k miles on it now and I'd say the gear whine I had is 80% reduced. Actually its gone so much that I forgot about it!