III. Neutral Difficult or Impossible to Find.
A. Faulty Linkage.
1. Disconnect control linkage at directional control arm. If
system now returns to neutral, the linkage to the control is out
of adjustment or binding in some way.
B. Control Valve Out Of Adjustment.
1. See II-D NOTE.
(Displacement control valve will not move out of
adjustment on its own, it has to be done by
2. If the hex nuts and slotted plug have been moved out of
adjustment, follow steps outlined on page 66.
C. Servo Cylinder Out of Adjustment.
1. Remove the two sleeve retainers.
2. Return the servo cylinders to their original position. When
the proper position of the servo cylinders was established at
the factory, both the servo cylinder and the pump housing
were marked with corresponding scribed lines. Matching
these lines will return the cylinder to its original position and
3. Reinstall the two sleeve retainers and restake, if necessary.
NOTE: Servo cylinders do not move out of position on their
own. If they get out of adjustment, it has to be done by
IV. System Operating Hot (TEMPERATURE GAUGE IN RED)
A. Oil Level Low.
1. Replenish oil supply.
B. Oil Cooler Clogged.
1. Clean cooler air passages.
C. Oil Cooler Being By-Passed.
1. Cooler by-pass valve, if used, stuck open.
1. One of the high pressure relief valves may be stuck partially
D. Internal Leakage. (Usually accompanied by loss
open. Install gauges and read the charge pressure and
operating pressure in both directions. If the operating
pressure is 200 PSI or more, lower than normal in one
direction and normal in the other, switch the high pressure
relief valves. If the low pressure also switches to the
opposite side of the circuit, disassemble, check and clean the
faulty (low) relief valve. Reinstall and recheck. Charge
pressure should be normal at all times.
2. Internal parts of pump or motor (or both) worn. Maximum
obtainable operating pressure lower than the normal high
pressure relief valve setting in both directions. When this
pressure is reached, charge pressure will drop to or very near
to zero. System will also be noisy at this point with the most
noise issuing from the unit that is most worn. If either unit is
considerably worn or damaged, the other unit should also be
carefully checked. Replace the worn parts in the units
affected or replace the complete unit.