What tranny to use for e->i swap

[Andy348]

I'm swapping out my M20B27 with the Getrag 260 (early model aluminum shifter) for an M20B25. The new B25 came with a 260 but it doesn't have the two flywheel sensors or the early model shifter.

I'm assuming that since I will be using the wiring from the B25 (entire harness), it doesn't matter that the B25 Tranny doesn't have the flywheel sensors, correct? And are the shifter set ups interchangeable?

Thanks

[jlevie]

You can use any Getrag 260 with an M20B25 engine since engine timing data is taken from the harmonic balancer and the #6 ignition wire. The early model cars used the shifter with the sheet metal shift console, which can be used on a late model transmission. But the late model shifter with the aluminum shift console is a better choice. The output flanges might be different, but they can be swapped.

Late model M20B25 engines (from 9/87) use a different cooling system with the expansion tank mounted on the left side of the engine bay. The easy solution is to swap out the water pump for an early model pump. An engine harness from late production (from 9/87) will need modification for the tach and econometer to work. Early production routes those signals via a pigtail off the engine harness near the DME connector, but late production routes them via C101. It is pretty easy to add the pigtail and connector to a late model harness.

Another possible issue is that early cars may have pin 20 of C101 grounded. That pin of the engine harness isn't used on an early M20B25 harness, but it is connected to the main relay on a late harness. If you power up the car you will smoke the harness. I clip that wire on the body side of C101.

[Andy348]

Perfect.

Thanks.