2009 Mercury Mariner Owner's Manual - Page 211

Driving D (Drive) with Grade Assist Pressing the transmission control switch on the side of the gearshift lever activates Grade Assist and cancels Overdrive. • Provides additional grade (engine) braking and extends lower gear operation on uphill climbs for hilly terrain or mountainous areas. • Provides additional engine braking through the automatic transmission shift strategy which reacts to vehicle inputs (vehicle acceleration, accelerator pedal, brake pedal and vehicle speed). • Allows the transmission to select gears that will provide the desired engine braking based on the vehicle inputs mentioned above. This will increase engine RPM during engine braking. • The grade assist lamp in the instrument cluster is illuminated. Grade Assist is designed to aid the driver with optimal gear selection in hilly terrain or mountainous areas but is not intended for normal operation. It is recommended that you return to O/D (overdrive mode) on flat terrain to provide the best fuel economy and transmission function. To return to normal D position (with O/D), press the transmission control switch again. • The Grade Assist lamp in the instrument cluster will not be illuminated. • The transmission will operate in gears one through six. O/D (overdrive mode) is automatically returned each time the engine is turned off. L (Low) • Provides maximum engine braking. • Will downshift to the lowest available gear for the current vehicle speed; allows for first gear when vehicle reaches slower speeds. 211 2009 Mariner (mrn) Owners Guide, 2nd Printing USA (fus)