Quote Originally Posted by leicesterboy15 View Post
Why is a 735i diff different to a 535i diff? Will a 740i diff be different to a 540i diff? Is the 3.64 LSD diff a worthwhile upgrade to my 540i auto? I thought the LSD diff was the best? Questions questions......sounds like you're having fun anyway!
Hey man long time no speaky! Err... I've no idea why it's different, but I done some research on realoem and there seems to be two versions of the seals I bought and murphys law ensured they give me the wrong one! AND they have to be ordered from Z Germany...

The only differences between diffs generally from my research seems to be case size (540i's/M5's have large case, 535i/530i/525i have medium case)... I think you can make smaller case diff works in bigger frame cars if you really want to. Input/output flanges can also differ, enough I think mine are the same so don't have to mess with them!

LSD is preferred for fast cornering and reduced wheelspin as far as I'm aware, whereas I'm more of a 'nifty off the line' kinda guy and I'm not adverse to the odd chirp of the enduros from time to time LOL!

Looking at this http://www.bmwe34.net/E34main/Upgrade/Recipe.htm , I think a 3.64 would be quite a big jump up and might make your gears quite short?! A 3.15, 3.23 or 3.46 might suit your car but I suppose it depends on your driving style?! I don't mind shortening up the gears a little in order to gain acceleration personally... This may also be of some use to you incase you haven't seen it before: http://www.vinesauto.com/diffratio.htm

Seems like the 3.15 out of a 750il *should* swap into yours easy enough... Tempted?!