rif_raf and Hughes500 see if this makes sense.
rif_raf: I suppose I could argue that the full engine torque passes through part of the transmission gear train.
Hughes500: If you are pulling 100% in the hover and press the power pedal ( left one in US helis) you power up the tail rotor, this drag causes the main rotor to slow, thus you descend, but you will pull more collective to maintain the same height.
In a Bell 206... You are pulling 100% torque in a hover. You push in the power pedal. Your engine is kept from drooping by the governor and engine output speed remains the same. Your MRGB is going the same speed and wasn't even aware that the tail rotor demanded more torque from the engine. To the main xmsn, nothing has changed. Yes? No?