For the motor I choose the most commonly used reliable drive system used in EVs’, an Advance 9” DC motor. I weighs in at 143 pounds, dual shaft, series wound motor. The adapter plate is 1/2” aluminum plate that mates the transmission face to the motor. I elected not to use a clutch and direct coupled the motor to the transmission. I did use the spring and spline assembly from the clutch and mounted it to motor hub. This allows for some mis-alignment of the shafts and helps take up some of the shock in the system.
I had to layout where the shaft of the motor would reside once bolted up to the transmission and trim the input shaft for clearance. It ended up the two shafts mate within an 1/8 of an inch of each other once assembled.
Trimming the hardened transmission input shaft requires some patience for a clean flush cut. I wrapped the input shaft with damp rags to keep the shaft seal from getting damaged from excessive heat.
I left the transmission on the bench and put the motor in a transmission jack. This allowed me to adjust the elevation and pitch of the motor. The motor and hub slid easy onto the transmission. I then pulled it back of to measure the amount of distance between shafts (a piece of clay between the shafts), then put it back together. Note the trimmed transmission shaft with a slight bevel on the spline.
Here’s the motor all mounted, lock-tite, and ready to drop into the truck. THe two red wires are thermal sensors built into the motor. The four large brass lugs are the power connections to the motor. The extra shaft out the end will be for air conditioning and possibly for a regenerative braking system in the future.
I purchased all stainless hardware with lock nuts, and used removable locktite on all of the hardware and set screws. The spline shaft and motor shaft was coated with anti seize before assembly.
