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2006 M5
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Discussion Starter #1
Do anyone know if we can swap a E9X M3 Diff with ours? I know the flanges are the same size and I'm 99% sure the Pumpkins are interchangeable but what about the Differential case? Is it longer/shorter that ours?
I found a pretty good deal on a 3.85 Diff that was rebuilt and has upgraded clutches. It would be nice and save so much time if I could just swap out the whole unit instead of cracking the cases and removing the pumpkins. From researching Real OEM the majority of the parts are the same, just unsure about the case size. Maybe I'll just reach out to diffsonline to verify.
 

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There’s a lot of confusing terminology which is unavoidable. When I looked in to this, it looks like the exterior housing/case is different since there are different mounting points to the subframe between the cars. No surprise there.To be more clear, that’s generally referred to the pumpkin or diff housing. The contents inside are the differential itself, where the ring is bolted on to (I’ve heard this also referred to as the diff case/housing/pumpkin) and it is spun by the pinon. I’ve understood that’s it is the same dimensionally as the e92 M3. I don’t know for sure though. I’d be interested in knowing what diffsonline say.
 

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Discussion Starter #3
You sir are correct! The Pumpkin is the unit in its entirety that's my mistake, it's been a while. I will try to reach out to Dan tomorrow and see what he says, keep your fingers crossed. If they can be swapped without much modification then that would be a game changer for sure!
 

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Yeah it’s one of those terms that is constantly used interchangeably. I’m fairly certain the ring gear is completely interchangeable.
 

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Discussion Starter #5
Yeah it’s one of those terms that is constantly used interchangeably. I’m fairly certain the ring gear is completely interchangeable.
Yes from what I gather e46 M3, e9x M3 and e60 M5 rings are interchangeable is that correct?
 

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That’s what understand. Unclear to me is the internals of the clutch pack etc. If you do simply plop in another diff, you will need to do all the work to set backlash, pinion depth, gear pattern etc. That’s all very advanced DIY stuff but nothing specific to BMW.
 
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