My 2006 Mazda 3 front left window will go down about 3 inches and then stops. When I roll it back up, it gets to the top and makes a loud ... almost like a vibrating noise.

It seems like the motor works, so I'm thinking maybe it's just a regulator issue. At least that's what I'm hoping, since it will be about $150 cheaper to buy the regulator w/o the motor.

Thoughts?

Thanks!