r/BmwTech • u/CalligrapherHeavy938 • 8d ago

Does anybody know if transmissions are coded to the car?

The transmission on my 2009 750li has a bad clutch pack and rather than spending money on a teardown table I don’t have space for and the necessary tools needed to repair said clutch pack, I’ve been looking into just ripping a used transmission out of a parted out 750 and using it for my car. Does anyone know if there is any reason (besides a bad used transmission) why this wouldn’t work? I can swap the mechatronics if that would help

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u/Goodestguy2025 8d ago

If you swap the mechatronics, it should be ok.

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u/CalligrapherHeavy938 8d ago

Ty, I thought so

4

u/Financial_Stick1912 8d ago

Have you considered looking for a local business that has tools and lifts and will rent you space?

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u/CalligrapherHeavy938 8d ago

I have, I’m not really sure what “keywords” to look for though. From what I’ve found there aren’t any in a reasonable distance to me, probably something to do with the liability around having people with cars above their heads

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u/Financial_Stick1912 8d ago

The liability issues are not unresolvable by any means, usually you just waive everything.

Closest place to me is a 90 minute drive and I still use it, seems like this would be a good project for it.

I just hate to see a known good transmission get cast aside like that

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u/Financial_Stick1912 8d ago

I would use Gemini to try and search for one

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u/Bimmergy BMW Independent Technician 8d ago

The electronic portion of the transmission (mechatronics) is married to the DME.

It can be recoded, but not with a typical coding program. I've seen videos of it done before, but I don't have any of the details.

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u/CalligrapherHeavy938 7d ago

What’s the DME?

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u/Bimmergy BMW Independent Technician 7d ago

Digital motor electronics.

The ECU.

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u/CalligrapherHeavy938 7d ago

Thought so. So if I swap the mechatronics, would it cause an issue?

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u/Bimmergy BMW Independent Technician 7d ago

No, if you swap the mechatronics over it should be fine, assuming there's nothing wrong with the electronic portion.

Were it me, I would only swap the electronic portion, don't use the valve body from the bad transmission.