Transmissions for electric cars hasn't any difference (in game). Just make a tansmission then change the "slotType" to the transmission of the electric motor
I don't remember electric motors have transmissionn slot or they have rear diff slot, I think @Xupaun is right. Btw, the slot is not a matter at all, you can even add transmission to left mirror slot!
As long as it's something as basic as a transmission then the slot doesn't matter, but once you start messing with anything to do with wheels, you HAVE TO put everything in the proper slots. I think a transmission in a diff slot should work but would obviously need a new diff after it. But no idea how it will shift, or if it will at all.
Yeah I know I just wanted to let him know that he can put transmission in another slot like diff Why? In one of my cars that i don't remember I installed a mod and it added a AWD transmission to rear diff, so the rear diff car could be convert to an AWD car. (There where front and rear diff slots in that transmission) So, I think putting the transmission into diff slot will not break anything
After 1 hour trying to do it, figured out it's impossible. All of the electric motors in game have a built-in transmission. Even I tried to make a new motor but when type of a motor is "electricMotor" in jbeam file, the game automatically installs a transmission for it. And having 2 transmissions at a time is impossible and game gave me an error when I tried to install my transmission on it. Also, I changed the type to "combustionEngine" but I received an error again.