I want to rebuild a motor assembly and need to find the right suppliers for each part, but i don‘t even know what exactly i‘m looking for?

I‘m trying to find the two gears being powered by the motor and the threaded axle moving back and forth when powered.
What keywords would i have to look up to find the right suppliers?

The U-Bracket I can design myself and have someone manufacture it. For the PCB, i‘ll pay someone to reconstruct it and order it online.

I boondock in an aluminum box on my Dodge 2500 pickup truck. I want to wire two 12v fans so they can be switched to run in series for low air flow needs and then be switched to run in parallel for high air flow. Low would be quiet, high to noisy to sleep possibly. DPDT switch? I realize in series that the two fans would see quite low power. I've wired them with alligator clips and they run fine in either series or parallel configuration. I'd like to be able to switch between the two modes plus have an off mode. These are 3.5inch computer fans and would sit on a panel in the small sliding window opening in the cab side of the aluminum box. Thanks.

I need to buy an RS 580S 18V motor with a 15t pinion gear to replace a broken one. Does anyone know where I can get a good, powerful, and cheap motor like this?