JLG 1100SB Service Manual - Manual (Page 266)

SECTION 5 - HYDRAULICS
5-32 – JLG Lift – 3121265
5. Transmission Drives in one direction only
a. Are electrical connections to pump control pro-
portional solenoids correct, intact and without
defects?
Yes - Proceed to step 5.b
No - Rectify the problem
b. Check hot oil flushing valve cartridge #120
located in the Traction Control Manifold.
Remove and inspect flushing valve cartridge for
stuck spool or damaged cartridge "O"-ring seals
& backup rings.
c. Inspect "Make-Up" check valve cartridges,
#190.1-190.4, installed in the Traction Control
Manifold. Is a cartridge "stuck" open with debris
or is an "O"-ring failed?
No - Proceed to step 5.d
Yes - Clean/repair or replace Make-Up check
cartridge.
d. Swap high pressure relief valves in the transmis-
sion. Does the transmission drive in the other
direction?
No - Proceed to step 5.e
Yes - Repair/clean/adjust or replace high pres-
sure relief valve on the non-driving side
e. Replace "EP" control module. Does pump oper-
ate properly?
No - Replace or repair pump
Yes - Operate the transmission
6. Transmission Drives in Wrong Direction
a. Check to see if electrical connectors or wiring
have been swapped on the pump.
b. Check to determine want end of the machine the
boom is swung over.
7. Transmission Does Not Find or Hold Neutral
a. Does pump remain in neutral with electrical con-
nectors removed?
No - proceed to step 7.b
Yes - Check electrical system for signal problem
b. With electrical connectors removed and
machines wheels jacked off the ground and
engine running, momentarily apply 12 volt DC
signal (battery voltage) to a pump control sole-
noid. Does the pump return to neutral after the
12 volt signal is removed?
No - Apply 12 volts to opposite solenoid &
recheck.
No - Replace pump control module, repeat step
7.a
Yes - Possibly dirt was dislodged from control
module, re-check thoroughly to determine prob-
lem has definitely been resolved.
c. Check mechanical centering of the pumps
8. Transmission Drives at a High Noise Level
a. Are the wheel drive planetary reduction gear-
boxes filled to the correct level and do they have
the proper lubricant?
No - Fill gearbox with correct grade of oil to the
prescribed level.
Yes - Proceed to step 8.b
b. Is the engine flex plate and drive coupling cor-
rectly installed and aligned with the transmission
pump?
No - Install flex plate and bell housing per manu-
facturer's instructions
Yes - proceed to step 8.c
c. Is a rigid item or object contacting the resilient
mounted engine/pump assembly?
No - Proceed to step 8.d
Yes - Insure no item is contacting the unit, trans-
mitting air borne noise.
d. Is the suction pressure/vacuum at the charge
pumps inlets within recommended limits?
No - Return to step 1.h
Yes - Proceed to step 8.e
e. Is there air in the hydraulic fluid? This may be
indicated by foaming or milky colored oil.
No - Proceed to step 8.f
Yes - Deaerate the oil and inspect system for
cause of air induction. Check for loose or miss-
ing "O"-rings on face seal connections.