Its the buttons in the secondary clutch, take the rear clutch off turn it upside down, there is a snap ring on the back, take it off and the clutch will come apart, pay attention to what holes the spring is in, take the helix away from the sheaves and there are 3 buttons between them that are held by torks screws, these are probably shot. Replace them and be sure to turn the helix 1/3 turn to pre-load the spring, it works better if you have a buddy to help you, then replace the snap ring and enjoy. Dont jump it and hit the ground with the tires spinning and it will last a long time.