Member
No, no, and no.
E39 M5 and E60 M5, are longer, so require an M5 length driveshaft. E60 CV is different from e39.
E39 M5 Diffs can use E32 output flanges to use 540 axles, or M5 axles with the original M5 output flanges. E32 flanges are as expensive as buying axles.
E60 M5 (M6) axle flanges are L+R and no known swap to other models. Every model has its own locking snap ring location. So again, M5 axles.
Plus, An e39 rear cover. Those are getting expensive.
Modifying costs, and aluminum welding=$$$. It's a doable swap, if you can do all that yourself.
Member
In that case we're no further ahead than where we started.
Sim Simma
Moderator
E60 M5 diffs are different fitment than E60 V8 diffs.
E60 M5 diff ratio is also very high because the E60 M5 revs very high, normally has 7 gears and it makes all its power up top. That ratio would not work well for an E39 V8 application.
I also don't see any reason welding the front bracket on is required for a stock power application. The torque from acceleration will be pushing against the stronger part of the ear if drilled. Offset poly bushings could also possibly be made to install it without drilling anything.
Member
I see no need to weld the additional bracket, I'm sure it was to eliminate the subframe cracking issues the e39 m5 in particular can have. It also seems odd having a part with massive load being applied be offset mounted. The diff mount bores are quite obviously just some extruded aluminum. You could probably find the right size off of McMaster carr. You can get brackets laser cut pretty cheap these days. If I find some extra time I might make the appropriate CAD files and drop them here so they are a public resource. Power to the people man!
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Last edited by seagreen323i; 05-05-2024 at 04:22 AM.
Member
As all options have been exhausted, I just ordered this 3.15 diff. It was just under $800 CAD. If I'm going to be changing diff mount rubbers, I might as well change the diff. Next step is wavetrac. That's going to be about $1800 CAD, ouch!Originally Posted by Iamthebull
What else is there to do, E39 M5 diffs are so expensive, over $1000 USD without the drive shaft.
Driveshaft flanges and driveshaft are at least another $1000 USD...
So at that rate might as well buy a brand new wavetrac...
Member+
3.15 is so useless for a DD car IMO. it's only good for a few fun moments but other than that makes zero sense. higher rpms @ highway means more consumption and higher noise.
Member
Well if it drifts, maybe I can drift it then!
Everyone to upgraded to 3.15 seems to love it.
I found just the ring and pinion for 3.15 from E39 M5.
I'm wondering if they'll fit into 2.81 diff to make it 3.15? I know M5 and 540i diffs are different size on the outside, but not sure about the ring and pinion.
https://www.ebay.ca/itm/196253467790...mis&media=COPY
Member+
they probably love the LSD, not 3.15I agree LSD is a must on these cars.
Sim Simma
Moderator
The idea of an offset bushing is just to make it a plug and play installation. I doubt an offset poly bushing would be any weaker in practice than drilling the front mounting ear. Probably paired best with poly rear diff bushings as well. May be a very small increase in NVH but with stock subframe bushings I doubt it'd be noticeable.
Member
Two months since I created this post, 3.15 diff is here!
The packaging was very poor and the lip got bent in a few places. Hopefully I can just unbend it.
At least, and surprisingly, the diff's paint is all nice and clean with no rust! I don't need to sandblast and paint it, which is nice!
Now just need to decide on then lsd
Member
You can just replace the flange with yours.
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Member
Good luck with the upgrade!
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