Dodge 2009 Ram Diesel Owner's Manual Supplement page 59

Overdrive Operation
The overdrive automatic transmission contains an elec-
tronically controlled 5th and 6th (Overdrive). The trans-
mission will automatically shift from DRIVE to Over-
drive if the following conditions are present:
• the shift lever is in DRIVE;
• the engine coolant has reached normal operating tem-
perature;
• vehicle speed is above approximately 30 mph
(48 km/h);
• the "TOW HAUL O/D OFF" switch has not been
activated;
• transmission
has reached
temperature.
NOTE: If the vehicle is started in extremely cold tem-
peratures, the transmission may not shift into Overdrive
and will automatically select the most desirable gear for
operation at this temperature. Normal operation will
resume when the transmission fluid temperature has
risen to a suitable level. Refer to the Note under "Torque
Converter Clutch" later in this section.
If the transmission temperature gets extremely hot, the
transmission will automatically select the most desirable
gear for operation at this temperature. If the transmission
temperature becomes hot enough the "Transmission
Temperature Warning Light" may illuminate and the
transmission may downshift out of Overdrive until the
transmission cools down. After cool down, the transmis-
sion will resume normal operation.
The transmission will downshift from Overdrive to
normal operating
DRIVE if the accelerator pedal is fully depressed at
vehicle speeds above approximately 35 mph (56 km/h).
STARTING AND OPERATING 57
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