I just bought a used 48 inch Bob Cat belt driven walk behind mower. It runs great, cuts perfect, but when idling there is a loud clapping noise. When I use speeds 1,2,and 3 the lawn mower moves perfectly fine and the clapping goes away. Gears 4 and 5 only work sometimes, and only with the clapping noise being louder. When they do work, the lawn mower randomly stops or each wheel will randomly stop at different times for a split second, and it is also nearly impossible to turn in those gears. This may or may not be related, but the belts on the sides that control the wheels are set up oddly too. The left side belt never stops turning even when you pull the lever on that side. the levers are both extremely loose, not sure if this is normal for a bob cat though since it is my first one. Any help or input would be appreciated, I'm trying to start repairing equipment myself instead of dragging it to the dealer and paying a fortune like I have been doing in the past.