JLG 1850SJ Service Manual - Manual (Page 274)

SECTION 5 - BASIC HYDRAULIC INFORMATION & HYDRAULIC SCHEMATICS
5-104 – JLG Lift – 3121619
12. Switch drive mode speed control from "turtle" to "rab-
bit". Gradually increase drive speed forward & reverse,
still with no load - wheels off ground.
13. With joystick in neutral, check for creep in neutral. If evi-
dent, 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 controls are connected so transmissions operate
in correct direction related to control input.
15. Continue to monitor all pressure gauges & correct any
irregularities.
NOTE: Step 17 disables machine's ability to release brakes.
16. Remove brake coil (keep electrical connection intact)
from brake release solenoid cartridge located on Trac-
tion Manifold. Stroke transmission pumps slightly (less
than 20%) and check setting of 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 transmission under no load conditions for
about 15 minutes to stabilize temperature and remove
any residual air from the fluid.
20. Lower machine to ground. Operate transmissions under
full and normal conditions.
21. Erratic operation may indicate there is still air trapped in
system. By working pump controls forward and reverse,
remaining air can be eliminated. System is free of air
when all functions can be operated smoothly and when
oil in reservoir is no longer aerated. (Usually less than
one hour of operation)
NOTE: If transmissions do not perform correctly after following
pre-start & start-up procedures, refer to relevant sections of
trouble-shooting procedures.