Ok so I bought a 2000 ranger 4.0 AT from an auction. Starter was hanging by the wires underneath. Bolts were missing so ordered the right starter bolts and bolted up the starter which appears new…turned engine with breaker bar and spins freely along with flex plate. Flexplate teeth look fine. Starter grinds but won’t engage to teeth. Starter is the right starter for vehicle per napa. Got new starter exact same thing. The problem I see is that the transmission and engine look like they were just replaced and installed. Im guessing maybe an older engine or something that has the wrong flex plate. How can I tell? Im assuming my problem is someone put the wrong parts or engine in. Everything looks great though and new I only paid like $240 for the whole truck…so it’s not like I’m out a lot. Truck is in nice shape with new tires. Looks like a weekend wrencher’s failed dreams. They put a ton of money in and I’m assuming couldn’t figure out the problem I’m sure that they caused. If I can get numbers off the trans, flex plate and engine would that help. I can’t find much info. Thank you.

 

You said, "Starter grinds but won’t engage to teeth."
Does "grind" mean spin? Starters spin as freely as any motor when they don't engage.

A "grinding" noise, to me, sounds like the depth of the starter is wrong.
Manufacturers use shims where the starter contacts its mounting location.
If the pinion gear sets too deeply, you get a grinding noise.

Are you saying the starting pinion gear revolves and doesn't move forward?
Try hot wiring the solenoid magnet at the starter.
The ignition switch might be the culprit.

Where was this auction held? Can anyone bid?