[Kevin Sevcik]

I believe the estimate is about 80-90% efficiency for those planetaries. Efficiency is typically considered as lost torque due to frictional losses in the gears meshing. As far as losing a pushing match.... That's dependent on FAR too many variables. If you're assuming the robots are exactly identical save for one having a more efficient gearbox... then yes, the less efficient one will lose. But there's so many other variables as to make that meaningless.