Includes the engine, torque converter, transmission, and front and rear drive axles-collectively known as the "four major components."
1. Engine
2. The torque converter assembly features three pumps: the working pump (supplying pressurized oil for lifting and bucket tilting), the steering pump (supplying pressurized oil for steering), and the transmission pump-also known as the travel pump-(supplying pressurized oil to the torque converter and transmission). On some models, a pilot pump is also mounted on the steering pump (supplying pilot pressure oil to the control valves).
3. Working hydraulic circuit: hydraulic oil tank, working pump, multi-way valve, lift cylinders, and bucket tilt cylinders.
4. Travel hydraulic circuit: transmission sump oil, travel pump; flow splits to the torque converter and the gear selection valve/transmission clutches.
5. Drivetrain: driveshaft, main differential, and wheel-end reduction gears.
6. Steering hydraulic circuit: oil tank, steering pump, flow stabilizer valve (or priority valve), steering unit, and steering cylinders.
7. Transmissions come in two types: integrated (planetary gear type) and separate (countershaft/fixed-axis type).
