Tascam 388 capstan issue. Do I need new motor?

[abramius]

Here's the issue; with or without tape on, the capstan will not spin, however, if I start the capstan with a gentle twist it will start to spin for a bit but then eventually slow to a stop again.
I took the bottom off and checked the belt, and it seems in good shape, though I'm unsure what the tension should be. Interestingly, if I take the belt off, the capstan motor spins freely without stopping!? So is this some sort of torque issue? That it can't pull the capstan? Do I just need a new belt?

BTW, I replaced all fuses, and cleaned the pinch roller because I thought it might be gunned up and slowing things down.

any help is appreciated,
thanks