5-44 4203780 First Edition
HYDROSTATIC POWER TRAIN
5
Figure 5-41: Secondary 4WD Shuttle Valve Test—
Blocking Disks at Rear Wheel Motor Inlets
NOTE
Verify engine rpm is within specification (2800 rpm ± 50)
to ensure accurate hydraulic test results.
18. Start engine, release park brake, and run at full
throttle (2800 rpm ± 50).
19. Adjust flow lock tool (1) to allow pump to produce 15
gpm (57 Lpm) in the forward direction.
20. Use the flow meter to warm the hydraulic oil. Turn the
flow meter valve until a reading of 1750 psi (121 bar)
or one half of the relief valve rating is reached. Warm
oil to 120—150° F (49—65° C); open valve fully after
operating temperature is reached.
21. After warming the hydraulic oil, verify flow lock tool is
adjusted to allow pump to produce 15 gpm (57 Lpm)
in the forward direction.
22. Engage 4WD switch in the forward position.
23. Slowly close flow meter valve until pressure reaches
2625 psi (181 bar). Read and record loaded flow.
24. Open flow meter valve, stop engine, and set park
brake. Return flow lock tool back to neutral position.
25. Calculate secondary 4WD shuttle valve leakage.
(Step 11 – Step 23 / Step 11 x 100 = Leak
Percentage)
Is secondary 4WD shuttle valve leakage 10% or
less?
YES The secondary 4WD shuttle valve is good.
Proceed to step 26.
NO Proceed to next question.
Is secondary 4WD shuttle valve leakage 11% to
20%?
YES The secondary 4WD shuttle valve is
marginal. Repair or replace secondary 4WD
shuttle valve as needed. (See “4WD Valve”
on page 5-53.) Continue to step 26.
NO Proceed to next question.
Is secondary 4WD shuttle valve leakage 21% or
more?
YES Repair or replace secondary 4WD shuttle
valve. (See “4WD Valve” on page 5-53.)
Continue to step 26.
26. Remove blocking disk from “L1” location (2) of 4WD
Valve.
TN2091
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