[cscottm]

Toughbox minis are supposed to be ran whilst lubricated for a period of time, andymark recommends 30 min.
You also should have a lot more lubrication on those gears. (they give you lots of the tacky grease, use it.
Thirdly, I would recommend running the motors unloaded, with grease for the extended period of time to properly "Wear in" the gears. (I don't know the correct word here)