Is the transmission system of tank hydraulic transmission or hydro-mechanical transmission?

These two concepts are applied in different fields.

Hydraulic transmission: it is a transmission mode that converts rotating mechanical energy into hydraulic pressure. Liquid works directly by pressure, and the change of pressure is reciprocating. Simply put, it is to control the reciprocating motion of the hydraulic cylinder. To convert it into rotary energy, it depends on the crank, just like the previous steam train.

Hydraulic transmission: it is to transfer the rotating mechanical energy to another rotating object, and the liquid does work by fluid power. Intuitively speaking, it's like putting a fan in the water, then putting another fan on the opposite side, blowing the previous fan against the latter fan and blowing it against the latter fan.

Therefore, the automatic gearbox of general tanks adopts hydraulic transmission, and the hydraulic pressure will not act on the gearbox, but only on the suspension system.