Differential Ratio??? which do i have??

[chll69]

How do you figure out what ratio you have for your differential unit?? i have a 1998 540i Automatic?? any one know where to look? i dont have the owners manual so i cant look there, are there any designations on the car?

[meanm50]

There is a little 'tag' on the diff itself. It should have some numbers like 'S346....' on it. If it begins with an 's', its limited slip, followed by the ratio.....so the 'S346' used for example would be a limited slip 3.46 diff. I don't know about the 540i for sure, but I am pretty sure its an S3.43? don't know for sure, but you could jack up the car and eliminate all the guessing.

[chll69]

Thanks!