Dodge 2006 DR Ram SRT-10 Owner's Manual page 208

208 STARTING AND OPERATING
NOTE: Do not exceed maximum engine speed.
"1" First
Use this position for driving up very steep hills and for
engine braking at low speeds (20 mph [32 km/h] or less)
when going downhill.
NOTE: Do not exceed a maximum engine speed of 5500
rpm.
Overdrive Operation
The four-speed overdrive automatic transmission con-
tains an electronically controlled fourth speed (Over-
drive). The transmission will automatically shift from
Drive to Overdrive if the following conditions are
present:
• the transmission selector is in Drive;