TM-9-2320-273-10

BASIC DRIVING GUIDELINES - CONTINUED

8. Monitor engine rpm on tachograph for appropriate ranges. Refer to Optimum Use

of Tachograph in this work package.

9. After prolonged engine operation above 1,500 rpm, run engine at idle for a

minimum of 3 minutes to allow sufficient cool down of turbocharger.

10. The recommended and most efficient cruising speed for highway use is the posted

legal speed limit at an engine speed of 1,800–1,900 rpm. Refer to Efficient and

Economic Driving Techniques in this work package.

11. To conserve fuel and reduce high rpm engine noise when operating in city traffic

or other reduced speed zones, match engine speed to road speed by selecting a

gear range that permits operating engine near, but not lower than 1,500 rpm.

12. When climbing uphill grades with the M915A1, accelerate at full throttle in gear

range 1-5 and allow transmission to upshift automatically, or for all vehicles

manually upshift transmission once engine speed reaches 2,000 rpm, one gear at a

time. Refer to Efficient and Economic Driving Techniques in this work package.

CAUTION

Never allow the engine to be pushed above the governed

rpm when rolling down a grade. Failure to comply may

result in damage to equipment.

NOTE

If a manual downshift or reverse shift is made at too high a

road speed, the transmission hydraulic system will prevent

the shift from occurring until the maximum lower speed is

reached.

13. When manually descending downhill grades, avoid over speeding engine by

manually downshifting to next lower gear range before reaching maximum rpm.

Figure 11. Fuel Gauge.

M915 THROUGH M920

M915A1

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