cranks open but doesn't close windows

Thanks for posting! It sounds like the gears on the inside of your operator are stripped. When this happens, the entire mechanism typically needs to be replaced. 

I'm happy to recommend a replacement but I will need to see a photo of the entire operator. I'll need to see a photo of the base without the cover as well as a photo of the arm(s) and how the operator attaches to the bottom of the swinging window sash.

Please don't hesitate to reach out with any other questions you might have.

Hello,

These can be replaced with the 39-107 Truth Hardware Operator Cover and the 39-114L Crank Handle. Although, replacing them will not address the issue you are having with not being able to close the window. 

The operator is stripped, so you'll need to replace the entire mechanism. I'm happy to identify the replacement but I'll need the information requested above to identify them.