Trapped air can be present inside the transmission. It needs purging for proper operation of the lawn tractor. The air most commonly accumulates during shipping, and Craftsman recommends purging before using the tractor for the first time. Purging should also be performed after a transmission has been serviced or replaced. Purging the transmission involves operating the freewheel control, starting the engine and other procedures. Normal operation can commence after the purging is completed.
Park the lawn tractor on a level surface, like a concrete apron, and make sure the engine is off with the brake engaged.
Turn the freewheel control to the freewheeling position and sit in the tractor seat. Start the engine and move the throttle to the "Slow" position. Slowly disengage the clutch with the control lever in "Neutral."
Move the motion control lever to the full forward position and hold it there for five seconds. Move the lever to the full reverse position and hold it for five seconds. Repeat this step three times and air will purge from the hydraulics.
Turn off the engine and set the brake. Re-engage the transmission with the freewheel control and then start the engine while sitting in the seat. Move the throttle control to the half-speed position, and with the motion control in "N," release the clutch with the pedal. Allow the tractor to move forward 5 feet and then reverse the tractor with the motion control. Go backward 5 feet, and repeat this step three times.