5-30 673831-Rev A
HYDROSTATIC POWER TRAIN
5
7. Start engine, move parking brake switch to the OFF
position, and run at full throttle (3000 rpm ± 50).
8. Adjust flow lock tool to allow pump to produce 15
gpm (57 lpm) in the forward direction.
9. Use the flow meter to warm the hydraulic oil. Turn the
flow meter valve (10) until a reading of 2030 psi (140
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.
10. After warming the hydraulic oil, verify flow lock tool is
adjusted to allow pump to produce 15 gpm (57 lpm)
in the forward direction.
11. Read and record no load flow.
12. Slowly close flow meter valve (10) until pressure
reaches 3045 psi (210 bar). Read and record loaded
flow.
13. Open flow meter valve (10), stop engine, and move
parking brake switch to the ON position. Return flow
lock tool back to neutral position.
14. Calculate traction pump leakage.
(Step 11 – Step 12 / Step 11 x 100 = Leak
Percentage)
Is traction pump leakage 10% or less?
YES The traction pump is good. Proceed to
step 15.
NO Proceed to next question.
Is traction pump leakage 11% to 20%?
YES The traction pump is marginal. Additional
testing is required. Continue to step 15.
NO Proceed to next question.
Is traction pump leakage 21% or more?
YES Repair or replace traction pump. (See
“Traction Pump” on page 5-40.)
Forward System Relief Valve Test
15. Open flow meter valve (10) completely before
starting engine.
Verify engine rpm is within specification (3000 rpm ± 50)
to ensure accurate hydraulic test results.
16. Start engine, move parking brake switch to the OFF
position, and run at full throttle (3000 rpm ± 50).
17. Adjust flow lock tool (1) to allow pump to produce 15
gpm (57 lpm) in the forward direction.
18. Use the flow meter to warm the hydraulic oil. Turn the
flow meter valve (10) until a reading of 2030 psi (140
bar) or one half of the relief valve rating is reached.
Warm oil to 120–150° F (49–65° C).
19. Continue to close flow meter valve (10) until zero flow
is obtained. Record forward system relief valve
pressure.
20. Open flow meter valve (10), stop engine, and move
parking brake switch to the ON position. Return flow
lock tool back to neutral position.
Is forward system relief pressure approximately
4060 psi (280 bar)?
YES Forward system relief valve is good. Proceed
to step 27.
NO Replace forward system relief valve. (See
“Traction Pump” on page 5-40.)
Reverse System Relief Valve Test
21. To test reverse system relief valve, reverse hoses
(2 and 6) at flow meter.
22. Open flow meter valve (10) completely before
starting engine.
Verify engine rpm is within specification (3000 rpm ± 50)
to ensure accurate hydraulic test results.
23. Start engine, move parking brake switch to the OFF
position, and run at full throttle (3000 rpm ± 50).
24. Adjust flow lock tool (1) to 15 gpm (57 lpm) in
reverse direction.
25. Close flow meter valve (10) until zero flow is obtained
and record reverse system relief valve pressure.
26. Open flow meter valve (10), stop engine, and move
parking brake switch to the ON position. Return flow
lock tool back to neutral position.
Is reverse system relief pressure approximately
4060 psi (280 bar)?
YES Reverse system relief valve is good. Proceed
to step 27.
NO Replace reverse system relief valve. (See
“Traction Pump” on page 5-40.)
27. If no further testing is required, disconnect and
remove test equipment. Install all hoses and fittings
as noted prior to removal.
28. Install and connect all components as noted prior to
test.
29. Check hydraulic oil level. Add oil as needed. (Refer to
“Safety, Operation, and Maintenance Manual” for oil
specifications.)
Do not exceed 4070 psi (281 bar) when testing
system relief valves or equipment damage may
occur.
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