E65 Differential swap into an E39 540i?

[ninetyseven1]

Does anyone know if this e65 750i rear end would just bolt in to my 540i? Looks like it would

[necsis]

It won't. Different mounting points.

[ninetyseven1]

It won't. Different mounting points.

Your positive? all the mounting points look the same though, even swapping the rear cover over to my e39 540i cover looks like all the bolts are in the exact same spots , it does appear to have an extra "ear" though on the drivers side on the front part of the diff but other than that all of the holes are the same. Picture 4 is the factory e39 540i diff, and the other pics are the e65 diff. looks like the cover from mine will bolt right on.

- - - Updated - - -

5.jpg2.jpg3.jpg4.jpg5.jpg

[ninetyseven1]

11 - Inside view of diff (1).jpgs-l1600.jpglook at this, left one is the e39 540i diff and right is the e65 750i diff. So, looks like my 540i rear cover will definatly fit no problem, i just wonder if the front ear (mounting point) and the extra ear on the drivers side would clear. If so , this is a 3.38 ratio diff and would be great.

[ninetyseven1]

11 - Inside view of diff (1).jpgs-l1600.jpglook at this, left one is the e39 540i diff and right is the e65 750i diff. So, looks like my 540i rear cover will definatly fit no problem, i just wonder if the front ear (mounting point) and the extra ear on the drivers side would clear. If so , this is a 3.38 ratio diff and would be great.

Can someone else confirm these rear ends will fit our 540i's? if so these 3.38 and 3.46 diffs are a dime a dozen and are going for less than $200.

[waters17]

Here are some diagrams for you to reference.

e65 diff
e65-diff.jpg

e39 Diff
e39-diff.jpg


e65 subframe
e65-sub.png

e39 subframe
e39-sub.png

[BimmrMeUpSnotty]

It’s not gonna work.The rear mounts are narrower from each other than on the E39. Why rewrite the book??? Source out a gear and pinion and get the gearing you are looking for.

[ninetyseven1]

It’s not gonna work.The rear mounts are narrower from each other than on the E39. Why rewrite the book??? Source out a gear and pinion and get the gearing you are looking for.

huh? rear mounts? you know the cover from the e39 fits right? the rear mounts of the diff are on the cover and i was thinking of using the e39 cover since it looks like the bolt patterns are identical. Is that what you are referring to?

[wagons ho]

Limited slip?
And what size rearend is the e65 classified as? 210mm 188mm?
Reweld the cradle and go e60 m5. Lower gear and sure grip.
Not sure these cars need lower gears though.

[ninetyseven1]

Limited slip?
And what size rearend is the e65 classified as? 210mm 188mm?
Reweld the cradle and go e60 m5. Lower gear and sure grip.
Not sure these cars need lower gears though.

The e65 is an open 210mm,

[CPHES]

Look at the difference in the front mount as well.

[TerraPhantm]

Front mount looks to be further from the center than the e39

[jclausen]

You will have to try it and report back

[philly98540]

Interesting as the rear bolt pattern seems a likely match, so the rear mounts should work out. The front will need some adapter or some welding to get it to work. The DS and stubs/axles may need work too.

The main problem is that is likely not worth the effort as this is still an open diff. Just a gear ratio change...