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Old 03-19-2013, 07:55 PM
e39530i5speed e39530i5speed is offline
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Location: United States
Join Date: Feb 2013
Posts: 5
Mein Auto: BMW/E39/530i
540i Manual Rear Differential Upgrade!

The 540i with manual transmissions has horrifically tall gearing. It has a 2.81:1 rear differential. I want to upgrade it to shorten the gearing. I know that 3.15:1's came stock on the 2003 M-Sport and M5 as well as all of the automatic 540i's. However, 3.15 isn't quite a large upgrade.

I look around and all of BMW's cars that use V8's such as the M62 and N62 of variety of sizes all tend to use differentials of 3.23 or 3.38. I think 3.46 is a bit too much, however 3.38 sounds reasonable as does a 3.23. These came on E60's and E65's 5&7 series cars.

I obviously want to buy a used open differential. I cannot however find anywhere if the flanges are interchangeable between differentials and if its a drop in replacement from the old ones meaning that they bolt to the frame in the same spots and you're good to go.

Thanks for any help!

Last edited by e39530i5speed; 03-19-2013 at 07:59 PM.
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