Want to upgrade my 2.81 diff on 95 540 auto

[rnrn]

Went to car-part.com and found some 88 750s but each auto yard said that the 94-95 540 diffs cannot accept others. I find that hard to believe...

Has anyone done this? Do I need an LSD if I'm running an open diff now?

[632 Regal]

No but it will have to be from a 540 or M car reason being the carrier and gears are larger than the 530 and 6 cylinder cars. I think the 750s are completely different housings but I cant look it up on the ETK here.

[Brandon J]

all e32 750 diffs fit your car. BMW has many standard parts and interchangeable parts. The diffs only came in big case and small case. No other combo for the e32s and e34s. So, don't listen to them and just get the diff. I would look into limited slip if available and also the one with the least mileage as well as one that has been on the shelf the least amount of time. Many places even keep the oil in the diff, which is good to keep parts from rusting or corroding.

Big Case: e32 750, e32 740, e34 540, e34 M5, all e31s
Small case: all 6cyl e32/4s, 530i

A ring and pinion from all big case diffs can fit into any big case diffs, including the e36 M3 euro big case, e46 M3, e39 M5, and so on. But I wouldn't go that route unless that was the last possible option. It can get costly to get it rebuilt and do it right.

[DrewZ]

I have one at the end of my 540i driveline. Early E32 750iLs had a 3.15 LSD; later ones had a lower gear (3.64 I think). LSD is a great upgrade from an open diff, and the change in gearing to a 3.15 is still well-suited for highway cruising.

Drew Zacharda
6-speed Touring

all e32 750 diffs fit your car. BMW has many standard parts and interchangeable parts. The diffs only came in big case and small case. No other combo for the e32s and e34s. So, don't listen to them and just get the diff. I would look into limited slip if available and also the one with the least mileage as well as one that has been on the shelf the least amount of time. Many places even keep the oil in the diff, which is good to keep parts from rusting or corroding.

Big Case: e32 750, e32 740, e34 540, e34 M5, all e31s
Small case: all 6cyl e32/4s, 530i

A ring and pinion from all big case diffs can fit into any big case diffs, including the e36 M3 euro big case, e46 M3, e39 M5, and so on. But I wouldn't go that route unless that was the last possible option. It can get costly to get it rebuilt and do it right.

[rnrn]

Ill try and find a 3.15 from a shop or parts house.