What diff do I have

[2fast]

How do I find out what diff I have on a 1989 535
I'm thinking of changing the oil this weekend.

Thank's

[bjl4776]

Check down towards the bottom of the page, it depends on if you have an auto or stick:

http://www.bmwe34.net/e34main/upgrade/Recipe.htm

[JonE]

You'll also want to know whether yours is an "open" diff. or a limited slip diff. There is a tag down on the differential with some numbers on it. If there is an "s" then it is a limited slip differential. Jacking the back wheels up and turning one of the wheels might indicate which one; if one wheel turns one way and the other one turns the opposite way then it is an open diff. I think the fluid requirements are different for a limited slip, you'll want to get the right stuff if you have one.

[Kalevera]

Probably a 3.91S (limited slip) if it's an automatic with the cold weather package. If you check under your rear seat, you'll find a slip of paper that has all of the factory codes and other such info stuffed in the cushion (unless someone removed it). If you take that and cross reference it by Sean & Johan's page, you can determine a lot of things about your car (not all -- but a lot of factory codes appear to be shared between the e34 and e32):

http://shrubbery.student.utwente.nl/...ptions750.html

Best, whit