Mercedes Benz produces their own gearboxes. The 7 speed was updated to a 9 speed. ZF makes transmissions for many cars including BMW, Dodge and others that use an 8 speed.

The ZF is a good choice for tuners and engine swappers because it's cheap and robust. MB makes it near impossible to take a transmission out of one MB and put it into another MB.

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With best regards

Al