Hello, I have an older KC70 and i am having trouble with what i can only describe feels like a the drive engage belt slipping when i press the foot pedal/hand lever to engage the forward of backward drive. I rented a friends machine yesterday to speed up an excavation and noticed how much more crisply his took off and maintained speed. Mine still works but it seems like its struggling more to grab whatever drives the tracks in forward or backward gears. I especially notice with a load. Any advice would help. Thanks very much. 
Paul
Paul