What diff oil to use.

[atc40]

Could someone please advise me on the correct oil to use in an open diff from an E30 325i tourer, 1989.
Thank you.

[Brianmoooore]

I'd use a synthetic 75W-90 these days.

[atc40]

Thanks for that Brian, any idea quantity?

[Brianmoooore]

188 diff. on a 325i, so 1.7 litres nominally.
Remove the filler plug before you remove the drain plug (just in case you find you can't undo the filler plug, and are stuck with an empty diff.), undo the drain plug, drain the old oil, replace the drain plug, and fill to the filler hole with the car level.

[atc40]

Again, thank you Brian.

[Doobit]

I just changed mine. I used 75W-90, on an original medium size open diff on a 325i. Took exactly 1.7L to fill it up. Very easy job. Bought comma from Halfords. As Brian says, filler plug before drain.

Only thing is the Getrag260 gearbox on the 325i takes 1.25 L. If the gearbox and the diff used the same oil (They use similar but not exactly the same) You can save a tenner on just buying 3L in total instead of 4L as there only sold in 1L bottles.

[atc40]

Cheers Doobit, useful info.