Ok I can see this
happening and I am sure it is really fun to back up really fast. But you won't
have the same power in going forward because there will still be part of the
resistor in parallel with the motor. In short (no pun intended) this is
probably a really bad idea, you are turning power into heat (the
ribbon resistor in the front of the tractor will be glowing red if you keep this
up), when going forward power this is power that should be used for pushing
snow. If you want more speed shift up a gear, basically when you
are pushing snow you should be going as fast as you can and still control
the tractor.