I am looking to replace my open diff from my 87 535i with a posi diff. From the BMW Bavarian auto recycling website it looks like all 82-88 325s with posi rear ends will bolt up as well as 528e,535i, 533i and 524td. Is this true and how do I decode the diff to tell if its posi. Is this a direct fit meaning un bolt mine and bolt the new one up or do I have to modify things like the mounts and drive shaft length.
Thanks