SlapHappy Drums

My 1985 van deciced it didn't want to roll the driver's side window all the way up. With the winter coming soon (and in the Pacific Northwest that means rain, and lots of it) I need to get this fixed. I can turn the roller until the window gets about an inch from the top and then the handle just clicks. I can push it up by hand and it is going straight up but it will slowly fall back down to an inch from being closed all the way. What part in the roller crank will I need to be looking at?

Hello. Just signed up. I own a 1985 Van with 165,000 miles. Mostly I will be looking for maintanance tips as my baby is slowly falling apart. Glad I found you all!