Mercedes-Benz Light Truck ML 320 Operator's Manual page 79

D The transmission automatically
upshifts through 5th gear. Position
"D" provides optimum driving
characteristics under all normal
operating conditions.
4 Upshift through 4th gear only.
Suitable for performance driving.
To shift from position "D" to "4",
push selector lever to the left.
3 Upshift through 3rd gear only.
Suitable for moderately steep hills.
Since the transmission does not shift
higher than 3rd gear, this gear
selection will allow use of the
engine's braking power downhill.
2 Upshift through 2nd gear only. For
driving in mountainous regions or
under extreme operating conditions.
This gear selection will allow use of
the engine's braking power when
descending steep grades.
1 In this position, the engine's braking
effect is utilized by shifting into 1st
gear. Use this position while
descending very steep or lengthy
downgrades and only at speeds
below 40 mph (60 km/h).
Important!
With selector lever in position "D", "4"
or "3", upshifting from 1st to 2nd to 3rd
gear is delayed depending on vehicle
speed and engine temperature. This
allows the catalytic converter to heat up
more quickly to operating temperatures.
During the brief warm-up period this
delayed upshift and increased engine
noise might be perceived as a
malfunction. However, neither the
engine nor transmission are negatiyely
affected by this mode of operation.
The delayed upshift is effective with
vehicle speeds below 31 mph (50 km/h)
at partial throttle and engine
temperatures below 95°F (35°C).
To avoid overrewing the engine when
the selector lever is moved to a lower
driving range, the transmission will not
shift to a lower gear, if the engine's
speed limit would be exceeded. In this
case there will be no downshift, even
when the vehicle speed reaches the
engine's speed limit of that gear, e.g. by
applying the service brakes. Continue
driving in the usual manner. The
transmission will then shift down
automatically.
To prevent the engine from laboring at
low RPM when driving uphill
gradients or with your vehicle heavily
loaded, the automatic transmission will
downshift when necessary to maintain
engine RPM within the best torque
range.
Warning!
On slippery road surfaces, never
downshift in order to obtain braking
action. This could result in drive
wheel slip and reduced vehicle
control. Your vehicle's ABS will not
prevent this type of loss of control.
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