I wanted to share a little video I made, taking apart a Toyota starter and explaining how it works:

The starter sits between the engine and transmission and is responsible for turning the engine over to start the combustion process. Here's what it looks like, removed from the car:



There's two parts to the starter, the solenoid and the electric motor:



The plunger inside the solenoid moves when its activated, causing the pinion gear to push out:



To get a better idea of the starter system, refer to this diagram:



I then cracked the starter in half and to my surprise, found a transmission of gears. This increases the motor's torque:



Here you can see where the plunger attaches to the pinion gear:



Next I took off the motor cover, and found brushes and the armature:





And here is the armature:



Finally, a system schematic illustrating how the starter works. Power flows through the solenoid's contacts to the starter motor. This means if the pinion gear isn't already engaged with the flywheel, the electric motor cannot turn.



Enjoy!

 

A curious question might be, why does one that comes with the car potentially last 12-15 years (on my Maxima it started to make a noise at 12, and failed at 15), but a remanufactured or "new" can last 0-3 months? I ate the labor DIY on jobs 2, 3, 4, but I could live with it. Many cars it is far more difficult to do, where intakes and cooling components come off, etc.

A Lexus tech told me don't ever core your original, rebuild it. Or, save it, even if you go aftermarket. You can't get the same quality remanuf. or aftermarket...wonder what tearing apart an original, vs. a "new" aftermarket or remanuf looks like. Maybe it's like an oil filter teardown where it's obvious the latter has lesser components? Same deal with brake calipers, Maxima has original fronts that are 20 y.o. The rears are on #4 or so, lousy rebuilds...

 

Its all in the quality of replacement components used in re manufactured components. While the casing and casting may be OEM, the materials used in say the brushes, solenoid contacts, plungers, springs and coils may not be up to OEM spec. Also, I'm sure aftermarket manufacturers have less quality control than OEM suppliers, so bad examples tend to pass through.