3.0 S Rear Diff Breather & Fluid Change

[Cotswold Polaris]

My recently acquired 3.0S came with a rear diff pinion seal leak and was overdue a diff fluid change. I was going to attempt replacing the seal, but the very helpful Jaguar Enthusiasts Club technical director suggested I first just give the breather a good clean out, and change the fluid - and see if that is enough to stop the seal bleeding, which may be enough to avoid the grief of the seal replacement job! Anyone had this work?

I gave the breather a good rasp clear with a cut down cable tie, and got the fluid changed, no significant problems and it was a nice mild day to be in the carport working on the car, with some tunes blasting out, instead of the actual day job!

As can be seen in photos, the old fluid was predictably black and plenty of gunk on the drain plug magnet. You can see how grimy the base of the diff was! This was 25k (in 5 years) since it was last changed. The level was definitely down a bit from the spec 0.86 litres so I’m glad I didn’t delay this task any further. It’s reassuring knowing there is lovely clean Castro BOT720 in the diff again and I saved a wad doing it myself!

[Cotswold Polaris]

The scrubbed a bit cleaner diff casing so I can now monitor if the pinion seal continues to bleed. Fingers crossed