make sure you have tightened every setscrew. The pulley on the main shaft is most likely slipping, if the insert was not aligned correctly. What I use, is a standard cap screw or tap to chase it before mounting it on the main shaft. it does not need to be super tightened, just snug after you get everything turning, you do need to make sure that everything is turning in correct direction. when the main rotor turns counterclockwise, the TR need to turn clockwise.