Craftsman 917.289240 has gap under bypass arm on transaxle. The transaxle has a hook sticking out the back of the tractor frame. The hook connects to this arm and, when pulled disconnects the wheels from the drive so the tractor can be pushed by hand. The lever looks like it should fit down closely onto the case below it, but instead there's this gap. Should I worry about dirt getting into the transaxle that way? Bypass arm is part number 412032 in parts list that came with tractor.