JLG 1850SJ, Service And Maintenance Manual, Page: 423 / 712

SECTION 5 - BASIC HYDRAULIC INFORMATION & HYDRAULIC SCHEMATICS
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10. Operate the drive system in the "turtle mode", forward
and reverse.
11. De-aerate the system by bleeding fluid from the Ma &
Mb ports.
12. Switch the drive mode speed control from "turtle" to
"rabbit". Gradually increase drive speed forward &
reverse, still with no load - wheels off the ground.
13. With the joystick in neutral, check for creep in neutral. If
evident, most likely dirt is present in the proportional
pump control, an incorrect electrical signal is present on
the pump's electrical control(s) or the control was not
centered properly when overhauled. See service manual
for centering instructions.
14. Check that the controls are connected so that the trans-
missions operate in the correct direction related to con-
trol input.
15. Continue to monitor all pressure gauges & correct any
irregularities.
16. Remove the brake coil (leaving the electrical connection
intact) from the brake release solenoid cartridge located
on the Traction Manifold. This disables the machine's
ability to release the brakes! Stroke the transmission
pumps slightly (less than 20%) and check the setting of
the high pressure cross port relief valves. Setting should
be 5000 psi +50 psi, - 0 psi (344.7 bar +3.4 bar, -0 bar).
Install 0-6000 psi (0 - 415 bar) gauges on Pump ports Ma
& Mb.
17. Check oil level & temperature.
18. Remove and inspect charge pressure oil filter, replace
with new element.
19. Operate the transmission under no load conditions for
about 15 minutes to stabilize the temperature and
remove any residual air from the fluid.
20. Set the machine back on the ground. Operate the trans-
missions under full and normal conditions.
21. Erratic operation may indicate there is still air trapped in
the system. By working the pump controls forward and
reverse the remaining air can be eliminated. The system
is free of air when all functions can be operated
smoothly and when the oil in the reservoir is no longer
aerated. (Usually less than one hour of operation)
NOTE: If the transmissions do not perform correctly after follow-
ing the pre-start & start-up procedures, refer to the relevant
sections of the trouble-shooting procedures.