Sears SS16 garden tractor electric linear actuator parts?

Hello from Southern Illinois. I have two, mid-1970s model Sears SS16 garden tractors and one Sears GT5000. One of the SS16s has a Sears electric linear actuator on the 3-pt hitch but it needs a new spur gear pinion (is attached to the motor shaft). From what I've been able to determine, this model actuator had no limit switches but relied instead on the "safety clutch" design of the gears. What this means is that when the actuator reached the end of its travel in either direction and you still held the control switch engaged, the small pinion gear on the motor shaft would "slip" out of mesh with the gear it was in engagement with and just continue to spin tooth-on-tooth until the switch was released. Not the best idea for a clutch, but probably what was most cost-effective in the mid-seventies. All that being said, I have tried locating a source for a replacement pinion as that is all I need to put my unit back in use. Can anyone suggest where I might find such a gear?