TM-9-2320-273-10

TRUCK, TRACTOR, LINE HAUL; LIGHT EQUIPMENT TRANSPORTER; TRUCK CHASSIS; MEDIUM EQUIPMENT TRANSPORTER

TECHNICAL MANUAL; OPERATOR’S MANUAL

DECEMBER 2012

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EFFICIENT AND ECONOMICAL DRIVING TECHNIQUES (M915A1)

The following driving techniques should be learned to achieve efficiency, economy, and

safe operation in the M915A1.

WARNING

Due to increased weight and raised center of gravity on

vehicles equipped with Crew Protection Kit, vehicle operator

must be aware of differences in driving characteristics and

adjust driving accordingly. Failure to comply may result in

damage to equipment or possible injury or death to

personnel. Seek medical attention in the event of an injury.

Driving at Highway Speeds

NOTE

The transmission lockup clutch automatically engages after

load is rolling and torque demand is low, and automatically

disengages at lower tractor speeds. When engaged, increased

fuel economy is achieved at highway cruising speeds.

1. Learn to identify transmission lockup clutch engagement/disengagement. Lockup

engagement is felt similar to transmission gear range shifts. In addition, a slight

change in engine sound can be heard when lockup occurs, due to a drop in rpm.

With experience it is possible to tell the difference between gear range changes

and lockup engagement/disengagement.

2. When driving conditions permit, maintain legal highway speed in gear range 1-5

(Figure 13, Item 1). Gear range 1-5 (Figure 13, Item 1) permits running the

engine below its governed speed (preferably 10–20 percent below governed

speed), and affords better fuel economy than at higher engine speeds. The

recommended normal highway cruising range is 1,800–1,900 rpm.

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