ORIGINAL: chevyderek72

Richard- the traxxas high stall spring works great, it takes more rpms to launch, so you get a better take off. i think its part number 4146x

Desmond- Your slipper clutch might be loose. There should be 3 sets of gears on different shafts, the first one which had the spur and the other metal gear on it has a slipper clutch. If thats loose it will just spin, check that, thats what it sounds like.