Oh ok thanks Dus, I think I may have found the reason the car is going so slow, I took apart the transmission box and it all seems fine inside greased up etc, but now I have it all back together sat flat on the table I've noticed the big cog (above the motor) moves almost 180 degrees before it actually moves the motor round enough for both rear wheels to move, could this be whats making the car go so slow or is there supposed to be play like that? The cogs are aligned fine and they are close together so its not slipping.