K5SS Kitchenaid mixer loud, won't really SPIN?

Hey everyone. My kitchenaid mixer (K5SS) is exceedingly loud and won't really spin. What I mean by it wont really spin is that it turns 1/4 of the way and stops... wait about another minute or so and it might turn another 1/4. All the while, the motor is working but theres BARELY any movement. I checked the gears and they don't look stripped. Is it possible that they ARE but I'm just not able to tell? If it helps, I have the original hobart metal gears... Thanks!