I have a 60 inch mower deck under an LT180. Recently we had a real trash mover rain in our area. 27 inches in 14 hours. After mowing at the highest setting, the mower blade engaging arm keeps slipping out and turning off the blades.

I have cleaned out the debris build-up around the pulleys but it still keeps jumping out. I checked the plastic arm under the dash and it does not appear to have shifted and looks to be okay. Any thoughts where I should check next?