Starter issues... How to change out the starter

I'd check the wiring circuits at the starter for voltage. Usually there are two hot circuits at the starter, one is battery voltage, hot all the time. The other circuit gets feed from ignition switch crank position. Also, that circuit usually goes through the neutral switch.

If you have good voltage and ground for the starter, yeah, suspect the starter. Some of the national brand auto stores will test your starter, if you take it to them.

Any testing at the starter, make sure tranny is in park or neutral and the parking brake is set. I'll check for removal.

Starter removal, take negative battery cable loose. Safely raise and support the vehicle. There may be a lower air-deflector that you have to remove. Remove torque converter cover. Take electrical connectors loose from starter solenoid. Remove starter bolts, lower starter. If any shims for starter, make sure you put back in same place.