Peterbilt Medium Duty Trucks Operator's Manual after 1-07

Operating Instructions
countershaft gear (which lubricates the transmission components
by oil splash) will only be turning at idle speed.
Descending a Grade
WARNING! Do not hold the brake pedal down
too long or too often while going down a steep
or long grade. This could cause the brakes to
overheat and reduce their effectiveness. As a
result, the vehicle will not slow down at the
usual rate. To reduce the risk of personal injury
and/or an accident, before going down a steep
or long grade, reduce speed and shift the transmission
into a lower gear to help control your
vehicle speed. Failure to follow procedures for
proper downhill operation could result in loss of
vehicle control.
Engine Overspeed
CAUTION: To avoid engine damage, do not let
the engine rpm go beyond the maximum governed
rpm—valve damage could result if overspeed
conditions occur.
Driving Tips And Techniques
NOTE: Often these recommendations are secondary
to maintaining an adequate and safe
speed relative to the surrounding traffic and road
conditions.
Operate the engine within the optimum engine rpm range
and do not allow the rpm's to exceed the maximum governed
speed. See your Engine Operation and Maintenance
manual for information regarding engine rpm.
When the engine is used as a brake to control vehicle
speed (e.g., while driving down a grade), do not allow the
engine rpm to exceed maximum governed speed.
Under normal load and road conditions operate the
engine in the lower end of the range.
Use of Tachometer
The tachometer is an instrument that aids in obtaining the
best performance of the engine and manual transmission,
serving as a guide for shifting gears.
Refer to the Engine Operation and Maintenance manual
for optimum engine rpm.
Medium Duty (R10/06) Y53-6008 – 99 –