Open up the case and replace the B772 transistor on the circuit board.
Reverse
no
It depends on the car. I wouldn't try to find out if I were you. The faster you go in reverse, the easier it is to lose control.
yes but clean the car after
It is quite fast for the average RC car except for now there are RC cars are available to go 100 MPH
It makes the car go.
i have both and my nitro gas goes faster than the gas
usually forward but if you shift to "R" then they go backwards
You have transmission problems, see your local transmission shop.
Yes, if the vehicle has an "open" differential.
about 50
It means the transmission is bad.