Garagistic M30 Swap Guide- Transmission

There are a few transmissions from which to choose. For the purposes of an imperative write-up, a factory E28 Transmission 5 speed (Getrag 260/6) will suffice. The flywheel/clutch that I suggested in clutch/flywheel section is made for that specific transmission. If you get a transmission from an older E23,E24, or E28, remember that you will have the old electrical systems from those cars, so you will see the two spots for the reference and crank sensors on the flywheel area at the bell housing. You can still use this transmission anyway as the bell housing bolts WILL match up, but you can just ignore the spots for the sensors. They will not be used. Plug them up or leave them. The stock E30 tranny cross member is a perfect fit to hold the E28 tranny and should perform as a check for a square fit within the transmission bay in the car.

What I explain below is the tools required to install the transmission to the engine block and ensure that it is done properly.


While the engine is outside of the car, install the transmission to the bell housing of the engine. This assumes that you installed the clutch correctly as in preventative maintenance.

You must install your guibo to the output of the transmission. Your transmission will have the rear output shaft in accordance with the tri-prong holes appx 3.12” apart. THIS IS THE DIMENSION FOR THE BIGGER GUIBO. See Figure 24 for details.

 GOOD: o 3.12” = 1987 325e, ’88 325 supereta

 BAD: o 2.6” = Any 325i E30

Figure 10 shows the mounting locations and bolt style that is necessary to mount the transmission bell housing to the M30 Engine block. Note in Figure 11, not all transmissions are identical.  Some transmissions have a removable bell housing.  There is no obvious advantage to one over the other.E28 Transmission from ebay… w/ E30 tranny bracket (kept from my E30)