ELECTRICAL SYSTEM - TM-55-1740-200-140022

TM 55-1740-200-14

2-19. DIFFERENTIAL LOCK LEVER. The differential

(4) and, because of pressure differential within the

lock lever (10) controls the differential action of the

chamber, forces the booster plunger (7) forward to

transfer case. When the lever is in forward position, the

hydraulically actuate the wheel cylinders. The booster

differential is unlocked. When in the rear position, the

plunger is spring loaded to return to normal position

differential is locked.

when the brake pedal is released. If for any reason there

should be no vacuum, the system will operate as a

2-20. PARKING BRAKE. The parking brake lever (1)

conventional hydraulic brake system.

controls the mechanical brake on the transmission. Pulling

the lever up and back applies the brake. In forward

position the brake is released. Clockwise rotation of the

2-14. ELECTRICAL SYSTEM. The tractor electrical

slack adjustment tip will take up slack.

system (figure 2-3) is a 12 volt system. Electrical power

is produced by the generator (10) and stored in the

2 - 2 1 . TRANSMISSION SHIFT LEVER. The

battery (7). The battery is protected from overcharging

transmission shift lever (5) operates the transmission

by a voltage regulator (1 1). A key operated ignition

starter switch controls all circuits, other than horn or

through five forward speeds and one reverse speed. Gear

lights, energizes the starter motor (9) and provides for

positions are shown on the instruction plate mounted to

the left of the instrument cluster.

accessory operation without engine operation. All circuits,

other than the starter motor circuit and clutch actuating

2-22. DIMMER SWITCH. Foot operation of the dimmer

circuit are protected by circuit breakers which are

switch (3) selects high headlight beam or low headlight

automatically reset after circuit overload. The starter

beam.

motor control is contained within the ignition switch. A

spotlight (4), floodlight (5), combined stop, and tailight

2-23. CLUTCH CONTROL. The solenoid valve control

(6), and headlights (1 and 8) are provided for night

switch located on the gearshift knob (6) disengages the

operation. The heater fan (2) and windshield wipers (3)

clutch when pressed. When pressure is released the clutch

are electrically operated. Tractors are radio suppressed in

will automatically engage.

accordance with Military Specification MIL-S-13079 for

Non-Tactical Vehicles.

2-24. BRAKE PEDAL. The brake pedal (2) is used to

slow and stop the tractor. Gradual pressure should be

applied for smooth operation. The pedal will return to

2-15. OPERATING INSTRUCTIONS.

normal position when pressure is released.

2-16. CONTROLS AND GAGES. Prior to actual tractor

2-25. ACCELERATOR. The accelerator pedal (9)

operation, the operator shall be familiar with the purpose

actuates the carburetor throttle linkage to increase or

and use of all controls and gages.

decrease engine speed. The accelerator should work

smoothly and return to idle position when pressure is

2-17. STEERING WHEEL. Movement of the steering

released.

wheel (8, figure 2-4) actuates the front wheels to steer

the tractor in the conventional manner.

2-26. CHOKE CONTROL. The choke control (1, figure

2-5) is used to provide richer fuel mixture during engine

2-18. REAR WHEEL STEERING LEVER. The rear

wheel steering lever (7) controls the rear wheel steering

warmup or for cold weather starting. To operate the

mechanism. By pushing the lever left or right, the rear

choke, pull control out from the panel as necessary.

wheels will be directed right or left thus turning the

During engine warmup, adjust choke as required.

tractor in the same direction as the motion of the lever.

2-27. IGNITION STARTER SWITCH. The ignition

Upon release of the lever, the rear wheels will return to

starter switch (2) is key operated. To actuate the

the straight ahead position.

electrical system, insert the key and turn clockwise to the

first position. To actuate starter motor, turn clockwise to

second position. Upon release, key will return to the first

position. T o operate accessories only, turn key

counterclock wise.

The differential lock lever should be in the

rear position only when one axle is slipping.

2-28. WINDSHIELD WIPER SWITCH. The windshield

Never drive under good tractive conditions

wiper switch (3) controls both windshield wipers. Pull

with the lever in the rear position.

switch out to start wipers; push switch in to stop.

2-4