KKK-B-1579 Buses, Motor: School, With High Headroom, 20-, 28-, 36-, 44-, 58- Passenger, Two-Wheel DriveThis specification covers gasoline and diesel, engine driven, high headroom, two wheel drive school buses. Buses shall have an engine mounted partially \(snub nose\) or completely forward of the windshield. Vehicles procured under this specification are commercial items which shall be warranted \(by a single prime contractor\) as specified in 6.4 or in procurement documents.

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KKK-B-1579B

tank and tank connections by securely attached metal shields at any point where it is 12 inches or

less from tank, tank connections, or any fuel line connections.

3.4.5 Transmission. Transmission input torque capacity shall be at least equal to

maximum torque delivered by the engine.

3.4.5.1 Automatic transmission. Unless otherwise specified (see 3.4.5.2), a continuous

drive, automatic transmission shall be provided. The transmission shall include a hydraulic

torque converter and not less than four forward gear ratios. Normal driving range selector

position shall provide not less than four gear ratios without movement of the selector.

3.4.5.2 Manual transmission. When specified (see 6.2), manufacturer's standard

manually shifted transmission shall be furnished. Transmission shall provide one reverse speed

and forward speeds as follows:

Type I, II, VI, and VII

- Four forward speeds, synchronized shift in second, third, and

direct drive.

Type III, IV, and V

- Five forward speeds, synchronized shift in at least the four

highest forward speeds.

3.4.5.2.1 Clutch. Clutch shall be the largest capacity offered for the size of engine

furnished and with torque capacity exceeding maximum delivered engine torque.

3.4.6 Drive line components. Drive line components shall be adequate to transmit the

maximum delivered torque of the engine as developed through the maximum gear train

reduction. Propeller shaft guards shall be provided in accordance with Federal Motor Carrier

Safety Regulation 393.89.

3.4.7. Chassis frame. Chassis frame for bus body mounting shall be so designed and

constructed as to support body and load and to maintain stability under all operating conditions.

3.4.8 Suspension. Vehicle shall be equipped with suspension system with components

having a rated capacity at least equal to the load imposed on each member, measured at the

ground, with vehicle loaded to specified GVW. When suspension capacity is rated at the spring

pads, unsprung weight shall be deducted. Vehicle shall be equipped with hydraulic,

double-acting shock absorbers on the front and rear axles. If leaf-type front springs are used,

spring design shall provide double-wrap spring eye, at least at stationary end of front spring.