How do you know?
 

So I got a 45t integy motor from someone and he never ran it and didn't know if it was new or used, so I was wondering how do you know if a motor is in good shape without hooking it up to electronics? Cuz with my luck I'd hook it up and some how both the motor and esc would explode:shock:
I know that the shaft on it doesn't have any marks from tightening a pinion gear on to it? If that helpS

Pull the brushes to examine wear or potential damage, at which point you can also see the Comm and check it for the same things.

You could also open it up and break it down completely if you want to truly inspect it properly (check the windings, bearings etc.)

Repair what's needed if anything, give it a good cleaning and re-assemble it.

Edit: A good visual inspection should tell you if there's anything wrong with the motor without wiring it up and putting power to it. If it were me, I'd still fire it up on the bench before I installed it in a truck.

Yup, do a visual inspection. Check for anything that look unusual, if unsure throw up pics on here and people woll let you know.

If it doubt wire up a couple of AA batteries and just give it 3volts to check it turns over.