MIL-T-62255 Truck Tractor, Yard Type, 4 X 2, Xm878This specification covers diesel engine driven, four-wheel, two rear wheel drive truck-tractor, yard type, with a one man half cab, having a minimum gross vehicle weight rating GVWR of 43,500 pounds and a gross combination weight rating GCWR of 100,000 pounds. Vehicles under this specification shall be procured only from a manufacturer who meets the standard commercial and commercially proven component criteria. Vehicles shall be warranted by the manufacturer as specified in the procurement documents.

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MIL-T-62255C(AT)

3.4.19 Tool box. A tool box shall be provided. The tool box shall be mounted on the side of the vehicle. The tool box shall be 18 inches in height, 18 inches in width and not less than

5 inches in depth. A door with a continuous hinge and a hasp for a 1 1/2 inch padlock shall be furnished. The door shall be approximately 18 inches by 18 inches.

3.5 Hydraulic lift fifth wheel. Unless otherwise specified (see 6.2), a hydraulic lift fifth wheel shall be furnished. The hydraulic fifth wheel unit shall be power operated, all cast steel, heavy duty, with a rated capacity to lift and support an imposed load of not less than

50,000 pounds on the truck tractor fifth wheel assembly. The fifth wheel shall have a lifting range of not less than 16 inches, measured in a horizontal plane, from the top of the fifth wheel plate in its lowest position to the top of the plate in the fully raised position. When specified (see 3.5.5), the fifth wheel shall have a lifting range of 31 inches, from the lowest to the highest position (see table II.) Fifth wheel and its mounting structure shall have a design capacity to withstand a drawbar pull of 60,000 pounds without residual deformation to the mounting, fifth wheel or its vehicle structure. The fifth wheel shall be capable of being manually locked and

unlocked in event of hydraulic and pneumatic failure. The fifth wheel shall be of the fore and aft

rocking type with a 36 inch diameter cast steel coupler plate supplied with beveled approach forks. The cavity below the fifth wheel shall be provided with a water drain hole. Fifth wheel shall not interfere with the rear axle, differential or any hydraulic component. The inclined angle of the approach ramps shall be designed to accept the semitrailer when negotiating 14 degree ramps without any interference of the semitrailer undercarriage and the ramps. The top surface

of the inclined angle of the approach ramps shall provide clearance above the vehicle tires, when

coupling to a semitrailer, when the fifth wheel is tilted rearward to its maximum aft angle for coupling purposes. The approach ramps shall be of the box type, with top inside edges beveled, and the top surface of high tensile steel, to preclude kingpin being gouged or damaged. The vehicle fifth wheel assembly, its components and mounting, shall have sufficient structural integrity to accept the dynamic and static imposed loads when the towed vehicle has a center of gravity of 109 inches above ground level (see 3.2.9, Table II, NOTE). The fifth wheel unit shall conform to Federal Motor Carrier Safety Regulations 393.70 a, b, e and g; and 393.71. Mode of mounting the fifth wheel shall be equal or similar to SAE SP-354.

3.5.1 Fifth wheel subframe. The fifth wheel assembly shall be provided with an inclined ramp presenting a continuous slope for semitrailer approach. When a sub-frame is provided, it shall be mounted to the vehicle chassis frame rails. Means shall be provided to preclude