| |
| Illustration 1 | g00331808 |
|
(1) Torque converter scavenge pump section
(2) Torque converter charging pump section (3) Parking brake release pump section (4) Pulled unit brake cooling pump section (5) Cover for the torque converter scavenge screen | |
The pump has four sections:
- torque converter scavenge pump section (1)
- torque converter charging pump section (2)
- parking brake release pump section (3)
- pulled unit brake cooling pump section (4)
The pump is driven by a gear on the torque converter.
The torque converter scavenge section (1) is located on the drive end. This pump section takes oil from the bottom of the torque converter housing. The oil flows through a scavenge screen that is behind cover (5). The oil is then returned to the hydraulic tank.
The other three pump sections get oil from the hydraulic tank.
The torque converter charging section (2) sends the oil to the torque converter hydraulic filter, to the torque converter inlet relief valve, and to the torque converter.
The parking brake release section (3) sends oil to the parking brake release hydraulic filter. This oil flow is then divided. The parking and secondary brake valve receives some of the oil. This oil is used to release the spring applied parking brakes. The rest of the oil that was divided flows to the lockup clutch and to the traction control valve. This oil is used to engage the lockup clutch in the torque converter. The oil that is sent to the traction control valve is used as signal oil.
Pulled unit brake cooling pump section (4) sends oil to a manifold. There is an oil cooler relief valve that is located in the manifold. If the oil pressure achieves the relief setting, oil will be sent back to the torque converter, pulled unit, and brake section of the hydraulic tank. Normally, pump oil in the manifold is sent to the oil cooler for the pulled unit. The oil goes from the oil cooler to the pulled unit for brake cooling. After cooling the pulled unit wheel brakes, the oil returns to another manifold on the tractor. This manifold combines returning oil from the pulled unit with rear brake cooling oil from the pulled unit hydraulics and rear brake cooling gear pump. The oil is used for cooling the rear brakes on the tractor. The oil will then return to the torque converter, pulled unit, and brake section of the hydraulic tank.