Transmission hydraulic system and engineering machinery

The invention discloses a transmission hydraulic system and engineering machinery. The transmission hydraulic system comprises a torque converter, a torque converter holding valve, a gearbox control valve group, a first hydraulic pump, a second hydraulic pump and a lubricating and cooling oil way. The torque converter is provided with an oil inlet, an oil outlet and a locking control oil port. The torque converter locking valve is connected with the locking control oil port to control whether the torque converter is locked or not. The gearbox control valve group is used for controlling gear shifting of a gearbox and comprises a gearbox control oil port. An oil outlet of the first hydraulic pump is connected with an oil inlet of the torque converter so as to drive the torque converter to act. The lubricating and cooling oil way is connected with an oil outlet of the first hydraulic pump, and a rotating piece is arranged in the lubricating and cooling oil way so that oil flowing out of the first hydraulic pump