PROPEL TRANSMISSION
SUBSECTION 9B
When the pump swash plates are tilted, a positive stroke to
the pistons is created. This, in turn, at any given input
speed, produces a specific flow from the pump. This flow is
Make certain the pressure setting of the motor
transferred through high pressure lines to the motors Mov-
charge relief valve is below the pressure
ing the control lever to the opposite side of neutral, re-
setting of the pump charge relief valve to as-
verses the flow from the pumps and turns the motor output
sure that the cooling circuit will function prop-
shafts in the opposite direction.
erly.
Adjustment of the charge pressure in forward and reverse
REMOVAL
is accomplished by changing the shims behind the spring.
To remove a pump proceed as follows
INSPECT THE MOTOR CHARGE RELIEF VALVE. If charge
pressure is low (below 160 psi) in forward and reverse (okay
It is not necessary to remove the pump to per-
in neutral), the charge relief valve located in the motor
form repairs on the charge pump, controller,
manifold should be inspected. Remove the hex plug and
relief valve, or check valves. However, it is ex-
relief valve parts (see Figure 9B-9). Inspect for foreign ma-
tremely important that the disassembled pump
terial holding the poppet open, and for galling or wear on the
be protected from airborne dust. Contami-
poppet and seat in the manifold.
nants introduced directly into the pump, have
the greatest potential for causing damage. If
this protection cannot be provided, it is sug-
gested that the pump be removed from the ma-
chine and repaired in a clean environment.
1. Stop the engine and remove the battery ground cable.
2. Remove the sheet metal around the pump to allow re-
moval of the pump from the side of the machine.
3. Disconnect the electrical lead on the controller.
4. Tag and disconnect the charge pump inlet line, high
pressure pump inlet and outlet Iines, and the case drain
line Cap all lines to prevent the entry of contaminants and
plug all pump openings.
Figure 9B-9 Motor Charge Relief Valve
5. Wrap a sling around the pump, and attach a lifting de-
vice to the lifting sling.
6. Make a thorough inspection of the area around the pump
being removed to ensure that all electrical and hydraulic
lines are clear of the pump.
Make certain the pressure setting of the motor
charge relief valve is below the pressure
7. Remove the four capscrews which attach the pump to
setting of the pump charge relief valve to as-
the drive unit and lift the pump out of the machine. Remove
sure proper operation of the cooling circuit.
the gasket that seals the pump and drive unit.
Adjustment of the charge pressure in forward and reverse
is accomplished by changing the shims behind the spring.
OVERHAUL
GENERAL. These pumps should be replaced as complete
units or repaired to the limits allowed by the service kits.
PUMP (37Z289)
DESCRIPTION
This is a variable displacement, axial piston pump. Two
pumps are mounted on a pump drive in front of the engine.
Repairs beyond the kits explained below will
Engine horsepower is transmitted through the pump drrve
void the warranty on the pumps.
to the pumps The pump swash plates remain in neutral
until the operator moves the control lever in the cab. When
The following overhaul instructions describe the proce-
the operator moves the control lever the swash plate in the
dure for installing each of the kits.
pumps are tilted from neutral.
