When I first got my proslide(love it) I mowed in 3rd gear. However it seems like my Skag 36 Belt Drive WB 15 HP Kohler has gotten slower and slower. Now i mow in 4th gear Sometimes 5th easy. I usually mow 1/4 acre lots but yesterday I mowed a lot about 2 acres. By the time i was done it was barely moving in 4th gear. Is this a belt problem? The belt seems tight to me. Maybe as the belt heats up it stretches or glazes and slips? It seems the more I use it in the day the slower and slower it gets. Have I ruined my tranny? I guess buying a new belt would answer a lot but it looks fine to me. Just wondering if anybody else noticed this? BTW, the engine sounds and is running perfect and blade speed seems fine and it still cuts well.