Specifications

OPERATING THE TRANSMISSION STARTING AND OPERATING THE VEHICLE
– 98 – Y53-6008A
Medium Duty (R05/09)
The best engine performance and maximum economy is
obtained if gears are properly selected. This efficiency is
achieved by always selecting gears within optimum
engine rpm, which is where maximum torque and power
are obtained. For further information, see “
More Driving
Tips and Techniques” on page 127.
Shifting Gears in a New Vehicle
Shift carefully in a new vehicle. The transmission may be
a little stiff at first. Avoid gear clashing by closely following
these procedures.
When you are operating a new vehicle or one that has
been exposed to cold weather, you want the transmission
lubricant (fluid) to circulate and coat the contacting sur-
faces of the gears. Metal contacting metal in moving parts
may seriously damage your transmission—do not drive in
one gear for long periods of time until the transmission
lubricant has a chance to coat all contacting surfaces.
Carefully observe the free travel in the clutch for the first
few hundred miles. As the clutch lining wears and high
spots get worn smooth, you will get less free travel.
Clutch Brake and Travel (9–, 10–, and 11–Speed
Transmissions only)
These transmissions utilize a clutch brake, rather than
synchronizers. The clutch brake works by stopping all of
the gears in the transmission, allowing you to easily shift
into first gear or reverse without grinding gears. The total
stroke of the clutch pedal is about 10 inches. The first part
is the release stroke: the part that fully releases the clutch.
The last inch engages the clutch brake.
During hard-shifting with vehicle not moving
To apply the clutch brake (while the vehicle is
stopped) fully depress the clutch pedal to the floor-
board to stop the gears. With the throttle at idle, select
first gear then release the clutch pedal to let the vehi-
cle start forward, until the clutch is fully engaged. See
the transmission manufacturer's manual that is
included with your vehicle for further details.