1. GSE Training Services Presents
Stewart and Stevenson
GT-50 Paymover
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2. INTRODUCTION Stewart and Stevenson Model GT-50/50H Tow Tractor
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3. Objectives At the end of this training, the student should:
Be familiar with the various operator features of the Stewart and Stevenson GT-50/50H tow tractor
Know the location and function of operator controls, warning lights, and indicators
Location of access doors and major components
Understand the pre-operational checklists
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4. Text Conventions The GT50/50H is a medium weight aircraft tow tractor.
For the purposes of this training, “forward” or “front” is referenced from the driving position.
And the “left” side as looking forward toward the front of the unit.
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5. Legends Words in all capitals denote legends on the control panels.
Example: The engine runs continuously when the selector switch is set to the ON position.
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6. Key Lines
FWD
Directions may be indicated, and features keylined. Keyline numbers may repeat in successive chapters. 1
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7. WARNINGS, CAUTIONS, and Notes
WARNINGS, CAUTIONS, and Notes refer to specific items or operations of special interest to operators and maintenance personnel.
WARNINGS and CAUTIONS refer to operations which involve danger to personnel and equipment. Notes refer to procedures which make operations easier.
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8. Introduction
The GT50/50H is a diesel powered, four wheel drive tractor
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9. Operator position seats one driver and one passenger
Optional front cab to protect driver can be ordered
Tractor comes standard with two-wheel steering. Four-wheel, two mode or three mode steering can be ordered
Powered by a six-cylinder Deutz diesel engine with a Funk 2000 series automatic transmission
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10. Dimensions
188”
90”
Vehicle body length of the GT-50 is 188 inches without hitches. Wheelbase is 90 inches.
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11. With the optional cab, the vehicle height is 86 inches.
86”
With the optional cab, the vehicle height is 86 inches.
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12. And without the optional cab, 65 inches.
65”
And without the optional cab, 65 inches.
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13. 102”
10”
The tractor is 102 inches wide, and has a ground clearance of 10 inches.
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14. Tow tractors are rated by weight and drawbar pull.
The S&S GT-50 weighs 50,000 pounds.
The S&S GT50H weighs 60,000 pounds.
The tractive effort, or drawbar pull, can be 40,000 to 48,000 pounds, depending on surface conditions.
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15. 43 feet
The turning diameter is 43 feet, and the GT50 has a top speed of 15 MPH.
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16. Vehicle Data Plates
The unit’s ID placard can be found on the left end of the instrument panel, facing the driver’s door.
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17. ACCESS DOORS AND PANELS
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18. Access Doors
This tractor has the Martin 846 cab.
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19. It has a rearward hinging door on each side of cab for access to the driving compartment.
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20. When you open the door, avoid striking yourself with the mirror.
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21. Access to the engine compartment is through two upward hinging covers on the top of the body work.
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22. Each cover has two latches
Each cover has two latches. Lift the latch handle up (as shown), and turn 90º.
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23. A placard with service information may be found on the inside of the forward cover.
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24. A step on the right front fender and a hand grip on the cabin roof provides access to the engine compartment covers.
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25. Jack Points
A jacking adapter is stowed inside one of the front wheel wells.
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26. The adapter fits into the cavity provided next to each wheel.
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27. With the adapter installed, an axle jack can be placed under the adapter to lift the vehicle.
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28. OPERATOR CONTROLS AND INDICATORS
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29. Instrument Panel
The operator’s instrument panel contains the following switches and indicator groups:
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30. Illumination switches
Indicators
Illumination switches
Start switch and warning lights
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31. The indicators consist of:
ENGINE oil pressure gauge. The normal operating range is PSI.
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32. ENGINE coolant temperature gauge. Normally operates around 185° F.
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33. BATTERY, which is a voltmeter that indicates battery volts
BATTERY, which is a voltmeter that indicates battery volts. Normally around 13 volts.
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34. FUEL GAUGE, which show the amount of diesel in the tank.
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35. ENGINE hour meter, the standard Hobbs meter which shows total running time of the engine.
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36. The Engine Start Switch.
Switches consist of:
The Engine Start Switch.
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37. With the Deutz engine:
Set the engine switch to the RUN POSITION. The GLOW PLUG light above the switch will illuminate.
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38. When the glow plug light goes out, turn the switch to CRANK
When the glow plug light goes out, turn the switch to CRANK. When the engine starts, release the switch. It will return to the RUN position.
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39. HEADLIGHT switch. This two position toggle switch controls the headlights.
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40. The headlight and parking light
The headlight and parking light. The headlights have no provision for high beam.
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41. PARKING LIGHT switch. This two position toggle switch controls the parking lights; the amber lights on the front, and the red combination lights on the rear.
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42. The red rear combination tail and brake light.
The white back-up light will illuminate when the transmission is placed in any reverse position.
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43. The reverse warning horn, located inside this opening on the rear of the tractor, will also sound when the transmission is in reverse.
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44. HAZARD light switch. Turning this two position toggle switch on will flash the front amber parking lights and the red tail lights.
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45. PANEL LIGHT switch. This two position toggle switch turns on the instrument panel light.
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46. Panel light (arrow).
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47. STEERING MODE selector
STEERING MODE selector. This two position toggle switch controls the steering mode.
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48. The up position is COORD - for coordinated steering
The down position is TRACK - for track steering
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49. With coordinated steering, the rear wheels will steer in a direction opposite to, and in proportion to, the direction the front wheels are steering.
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50. And track is simply front wheel steering only.
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51. EMERGENCY STEERING PUMP
EMERGENCY STEERING PUMP. This two position toggle switch turns on the emergency steering pump in the event the main pump fails.
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52. Warning lights consist of:
GENERATOR NO CHARGE - Warns the operator that the charging system is not operative.
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53. HAND BRAKE ON - Warns the operator that the parking brake is set.
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54. ENGINE LOW OIL PRESSURE - Warns the operator that the engine oil pressure is below 5 PSI.
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55. ENGINE COOLANT TEMP OR LEVEL - Warns the operator the engine coolant is hotter than 185ºF, or level is too low for safe operation.
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56. BRAKE BOOSTER PUMP ON - Warns the operator that the brake booster pump is running.
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57. The TACHOMETER reads the engine RPM
The TACHOMETER reads the engine RPM. It is located at the far left end of the panel, to the left of the steering wheel.
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58. Heater/Defroster controls
At the far right end of the panel are the heater/defroster controls.
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59. At the top is the HEATER fan speed control
At the top is the HEATER fan speed control. It allows the operator to select OFF or LOW, MEDIUM, or HIGH speeds.
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60. The heater and fan are inside this box under the driver’s seat
The heater and fan are inside this box under the driver’s seat. The heater has a shutoff valve in the event it begins to leak.
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61. Below the HEATER switch are the WINDOW DEFROSTER pull knobs that control airflow to the front and rear windows. Pulling out these knobs turns on the fans that blow warm air across the windows.
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62. 2 1
The “front” knob turns on the outboard fan (1), and the “rear” knob turns on the inboard fan (2) under the passenger’s seat.
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63. Above the center of the panel, on the top of the dashboard, is a large red PARKING BRAKE ON light. This will illuminate any time the engine is running and the transmission is placed in forward or reverse while the parking brake is applied. This warns the operator to release the parking brake before moving the vehicle.
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64. Overhead Switch Panel
The overhead switch panel carries auxiliary controls. Overhead switches consist of:
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65. BEACON LIGHT - Which turns on the amber beacon on the roof of the cab.
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66. Beacon light.
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67. HITCH LIGHT - Which turns on the work light on the front of the cab.
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68. Hitch light, normally pointed toward the ground to illuminate the work area around the front hitch.
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69. The mirror next to the hitch light allows the driver to view the hitch.
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70. FAN - Which turns on the two ventilation fans in the cab.
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71. Ventilation fans (defogger fans).
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72. FRONT WIPER - Which turns on the left front windshield wiper.
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73. FRONT WIPER - Which turns on the right front windshield wiper.
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74. The rear window wiper may have it’s own switch on the motor body (arrow).
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75. The cab has a dome light attached to the ceiling
The cab has a dome light attached to the ceiling. It has it’s own switch. It may be turned on any time, regardless of the position of the ENGINE START switch.
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76. Transmission Shift Lever
The transmission shift lever is located on a box between the seats.
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77. The Funk 2000 transmission has six forward speeds, and three reverse.
The shift lever should always be placed in NEUTRAL (N), and the parking brake applied, prior to stopping the engine and leaving the vehicle.
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78. Directly behind the shift lever is a placard which explains the methods for towing the vehicle.
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79. Parking Brake Lever
To the right of the shift lever is the parking brake lever. Pull this lever up and back to set the parking brake.
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80. Driver’s Seat
The operator’s seat position can be adjusted. Moving the lever at the front edge of the seat (arrow) to the left will release the seat lock, allowing the operator to slide the seat fore and aft.
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81. Lifting the lever on the right side of the seat near the floor will allow the operator to raise or lower the seat.
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