pretty much we beat the crap out of this little thing ... we plan on gettin service manual and cracking it open just wanted to know if someone knew what the problem was

problem :
it still shifts up into all 3 gears but if u give it gas it just makes this loud rattling noise and doesnt go anywhere .. clutch maybe ?

 

Sounds like a clutch to me. Maybe the teeth on the inner gears are shot too. I'd take it apart and check it all over