Though it is not - I believe - the case of this specific Komatsu model, electric driven dumper trucks are in production, getting rid of the transmission, examples, JFYI:
Basically this kind of trucks have a huge diesel engine and electric generator and four electric motors, one for each wheel.
Power is lost in the generation and powering of the electric motors of course, but there is no transmission overhead (though there is a reduction gearbox on each motor anyway).
http://www.komatsuamerica.com/equipment/trucks/electric
http://www.cat.com/en_ID/products/new/equipment/off-highway-...
Basically this kind of trucks have a huge diesel engine and electric generator and four electric motors, one for each wheel.
Power is lost in the generation and powering of the electric motors of course, but there is no transmission overhead (though there is a reduction gearbox on each motor anyway).