it is hard to manually open and close the power door. The dealership says the motor is going bad and needs to be replaced. We only have 40,000 miles on the 2001. How do you replace the motor for the door?

Welcome to sliding door problem, this is common on the 2001 search under door also expensive fix to replace the motor which takes care of the problme for a few years I am now in my third motor in 4 years

Did you ever locate the problem?