[Bobboloo]

Depends on whether you're removing or installing.

Removal: motor only

Install: motor and tranny mated

I like to drop the motor without the tranny so I can leave the axles hooked up and the tranny in the chassis but when it comes time to install the motor I pull the tranny and mate it to the motor before I re-install. It's too hard to mate them with the motor on a jack IMO.