for the past month when i roll up my driver side power window..it would go up and just keept going up hitting the top part and making a loud clicking noise..well for the past week it will roll up but not all the way..it would go until there half an inch to an inch left of the window open and wont go up any more..when i took off the door panel it turns out that its the flat circular thing with all those teeth..the last 3 are bent up and not full..where can i purchase this at online? thanks