How is wheeltorque calculated?

I don't understand how wheeltorque is calculated in the engine debug app. With a manual transmission put in direct gear (1:1) it is equal to or just less than engine torque in all vehicles. It should be 3 times more than that from the torque increase through the diff. Im assuming its an addition of the torque at each wheel.

 

Ok hopefully its fixed next update. I am trying to figure out why the semi is so underpowered. I drive them in real life and I can tell something is off. Power is about right below 30 mph but at 60 there is half of what there should be. It is better this update, but I think rolling resistance is still too high.