Is a 3 speed wiper transmission teh same as a 2 speed?

Motor, switch and transmission linkage have to match. The mount "area" on the motor where the crank goes is sized/shaped differently depending on 2 vs 3 spd, so a 2spd crank arm wont fit properly on a 3spd motor and vice versa. Hope that makes sense.
Devil chicken explained it better lol.