Ford 2001 Mercury Cougar Owner's Manual page 165

Driving
R (Reverse)
With the gearshift in R (Reverse),
the vehicle will move backward.
Always come to a complete stop
before shifting into and out of
R (Reverse).
N (Neutral)
With the gearshift in N (Neutral),
the vehicle can be started and is
free to roll. Hold the brake pedal
down while in this gear.
D (Overdrive)
The normal driving condition for
the best fuel economy. Transaxle
operates in gears one through four.
D (Overdrive) can be deactivated
by pressing the transaxle control
switch on the side of the gearshift
lever. O/D OFF will illuminate in
the instrument cluster.
Drive (Drive) –
O/D off illuminated
Activate by pressing the transaxle
control switch on the underside of
the gearshift lever. The transaxle
operates in gears one through
three. D (Drive) provides more
engine braking than overdrive and
is useful whenever driving
conditions (i.e., city traffic, hilly
terrain, etc.) cause the transaxle to
excessively shift between D
(Overdrive) and D (Drive).