Overdrive Off - Chevrolet 4500 HD 2023 Manual

178 Driving and Operating
For safety reasons, the shift lock system
operates to prevent shifting of the selector
lever to any position other than P unless the
brake pedal is pressed and the starter switch
is in the ON position. When pulling away,
be sure to keep the brake pedal pressed as
you operate the selector lever. See Driver
Information Center (DIC) 0 64, Overdrive Off
Light 0 58, Automatic Transmission 0 169,
and Automatic Transmission Shift Lock
Control Function Check 0 265.

Overdrive Off

Overdrive Off Switch
Diesel vehicles have two overdrive gears (5th
and 6th). These two high speed gears
provide increased road speed, low running
noise and outstanding fuel efficiency.
Take advantage of overdrive whenever
possible.
Use the overdrive during normal driving.
When driving down long downhill roads
that require the engine brake, or when
driving on mountain roads or through city
centers, release the overdrive. Doing so
will reduce the number of gear changes
making the ride smoother.
If your vehicle is traveling at a speed
exceeding 101 km/h (63 MPH), it is not
possible to downshift from 6th gear to
5th gear.
If your vehicle is traveling at a speed
exceeding 78 km/h (49 MPH), it is not
possible to downshift from 5th gear to
4th gear.
Overdrive Off Switch : Press the overdrive
off switch (3) to turn the overdrive OFF (the
overdrive off indicator light comes on).
Press the switch again to release the
overdrive off (the overdrive off indicator
light goes off). See Overdrive Off Light 0 58.