Advice on E36 differential

[ph47jat]

I have bought a used tds bmw diff and its very rusty on outside. But the seller says the diff ran fine and smooth. Any way or checking it without opening up the diff

[Dez]

They always are rusty on the outside. They’re more or less unpainted from the factory and 30 years under a car inches off the road don’t do em any favours in the looks department.

I’d always pop the backplate off and have a look in any diff I’d bought before I fitted it though. For the price of a bit of sealant and some fresh oil it’s not worth hours of wasted labour fitting a duff one.

FWIW bmw diffs tend to feel ‘tight’ compared to other manufacturers, needing a bit of force to turn rather than being really free. I’d still open it up and look at the gear wear pattern (and check the ratio) before fitting though.

[legend]

clicky      although not a BMW guy, Martyn at Gas n Gears is a great source of all things gear related

[ph47jat]

Well I rotated the diff and it felt smooth, similar to way you would test a wheel bearing. That's mean anything lol. Also how would I find out what oil it takes? It's a bmw 2.56 tds diff. And how much oil

Nov 20, 2019 23:48:42 GMT Dez said:

They always are rusty on the outside. They’re more or less unpainted from the factory and 30 years under a car inches off the road don’t do em any favours in the looks department.

I’d always pop the backplate off and have a look in any diff I’d bought before I fitted it though. For the price of a bit of sealant and some fresh oil it’s not worth hours of wasted labour fitting a duff one.

FWIW bmw diffs tend to feel ‘tight’ compared to other manufacturers, needing a bit of force to turn rather than being really free. I’d still open it up and look at the gear wear pattern (and check the ratio) before fitting though.

[ChasR]

Nov 21, 2019 10:21:42 GMT ph47jat said:

Well I rotated the diff and it felt smooth, similar to way you would test a wheel bearing. That's mean anything lol. Also how would I find out what oil it takes? It's a bmw 2.56 tds diff. And how much oil

Nov 20, 2019 23:48:42 GMT Dez said:

They always are rusty on the outside. They’re more or less unpainted from the factory and 30 years under a car inches off the road don’t do em any favours in the looks department.

I’d always pop the backplate off and have a look in any diff I’d bought before I fitted it though. For the price of a bit of sealant and some fresh oil it’s not worth hours of wasted labour fitting a duff one.

FWIW bmw diffs tend to feel ‘tight’ compared to other manufacturers, needing a bit of force to turn rather than being really free. I’d still open it up and look at the gear wear pattern (and check the ratio) before fitting though.

According to RealOEM, that uses 75W90 GL5 oil. The factory oil is BMW Synthetik OSP, with part no. 83222365987. 1 litre should do the trick. But as always, fill to the drain plug level.