JLG Lull 1044C-54 II Series, Service Manual

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Transmission
31200079 8-13
8. Back flush the transmission oil cooler portion of the radiator or the oil
cooler (located behind the radiator) with oil and compressed air until all
foreign material is removed. Flushing in the direction of normal oil flow
does not adequately clean the cooler. If needed, remove the radiator or
oil cooler from the machine.
IMPORTANT:
DO NOT use flushing compounds for cleaning purposes.
9. Reassemble all components and fill the transmission with clean, fresh
Mobil 424 Tractor/Hydraulic Fluid through the dipstick tube opening.
Remove the dipstick and fill with approximately 19 quarts (18 liters) of
Mobil 424 Tractor/Hydraulic Fluid. Check the level by taking intermittent
dipstick readings as outlined in the appropriate Operator/Safety
Manual.
DO NOT overfill. Reinstall the dipstick when finished.
10. Run the engine for two minutes at idle to help prime the torque converter
and the transmission oil lines.
11. Recheck the level of the fluid in the transmission with the engine
running at idle.
12. Add Mobil 424 Tractor/Hydraulic Fluid as necessary to bring the fluid
level up until it reaches the FULL mark on the dipstick. Recheck the oil
level when it reaches operating temperature (180-200° F or 83-94° C).
13. Recheck all drain plugs, lines, connections, etc., for leaks, and tighten
where necessary.
Transmission Shift Logic
There are 8 relays, 9 diodes and 2 diode modules which make up the
transmission shift logic circuit. Fig. 8-12.The relays are labeled K11
through K17 (Relay K18 is not part of the transmission shift logic).
Relays K11 through K17 are part of harness assembly part number
4923246.Diodes D1 through D9 are also a part of harness assembly part
number 4923246. Relays K11 through K17 and Diodes D1 through D9 are
located in the cab in a small metal box behind the operator's seat on the
right side of the machine.The 2 diode modules are part of harness
assembly part number 4923243.The purpose of the diode modules is to
allow the solenoids to be energized and de-energized without adverse
effects on the rest of the transmission circuits only. They do not control
how the transmission shifts.The purpose of Diodes D1 through D9 is to
allow current flow in only one direction in a given wire or circuit. It is
extremely important that the polarity of the diodes in the circuit is correct or
the transmission will not shift as it was designed to.
The purpose of the relays is to control how the transmission shifts.
See Fig. 8-12 to determine when each of the relays is supposed to be
energized.