Chevrolet Low Cab Forward 4500 2019 Series Owner's Manual page 169

168 Driving and Operating
Driving Uphill or Downhill
Uphill driving:
With the selector lever in D6/D4,
if you press down on the accelerator
pedal, kickdown (change to a low
speed gear) may operate causing
the engine revolutions to suddenly
increase (increasing the speed).
Driving for a prolonged duration on
an uphill road with the selector lever
in D6/D4 may cause the automatic
transmission fluid to overheat.
Drive with the selector lever in the
D4 position to keep the engine
revolutions constant to enable
smoother driving with fewer
changes in engine revolutions.
Driving conditions
Normal uphill road
Steep uphill, steep slope, mountain
road with many sharp curves
Long uphill road
Downhill driving:
Do not overuse the foot brake. This
will cause the brakes to overheat,
reducing their effectiveness. On
long downward slopes or sharp
downhill sections of road, use the
engine brake together with the foot
brakes to control the speed.
With the selector lever in the D4
position, speeds below
121 km/h (75 MPH) will increase
engine braking action when
traveling downgrade.
You can increase engine braking by
driving with the selector lever in the
2 position.
Selector lever position
D4
2 or 1
2
To apply a stronger engine brake on
sharp downhill sections, shift the
selector lever to the 1 position when
required.
See Control of a Vehicle 0 130.
Driving at Low Speeds for
Sustained Periods
Any low speed applications such as
sweeper, road marking machinery,
trash collectors, highway striping or
moving, etc. require the following
treatment to prevent the automatic
transmission fluid (ATF) from
overheating:
Select 1 position during low speed
operation under 36 km/h (22 MPH).
Select 2 position during low speed
operation under 61 km/h (38 MPH).