MAX2000JP

Okay guys its crunch time. I only have 126 miles left on my warranty and my rear window is acting up. Heres the problem....When I roll the passenger side rear window up it makes a popping noise when the motor first enganges. It only happens when it goes up. Is this normal?? I have a suspicion that something is wrong with the motor, which means big $$$$ if not covered under warranty.