it stands for automatic 4 wheel drive, the What_does_a4wd_mean_on_a_gmc_envoydrive will engage when the vehicle senses tire slippage.
Good to use when driving on somewhat snow covered roads where some driving might be on the pavement some on snow. Not good to use the 4wd when on pavement especially when turning.
On a 2003 Ford Expedition : If you are driving on paved roads that are dry , for the best gas mileage , 2H But , you can also use A4WD ( Automatic four wheel drive ) on dry pavement A4WD is best for wet roads , snow , gravel because if the back wheels " slip " then some of the power is transferred to the front wheels
On a 1999 Ford Expedition : A4WD ( Automatic four Wheel Drive ) delivers power to the rear wheels and if the rear wheels lose traction ( slip ) some of the power is transfered to the front wheels
Bring your Expedition to a stop , with your foot on the brake pedal shift your transmission to NEUTRAL , then turn your selector dial to whichever setting you wish ( 2H / A4WD / 4 H) and then put your transmission in gear
If the pavement is dry I use 2H , that has power going to the rear wheels only and gives the best gas mileage If the pavement is wet I use A4WD ( automatic 4 wheel drive ) that way if the back wheels loose traction some of the power is transferred to the front wheels
A 1997 Ford Expedition is either rear wheel drive or it has the Control Trac 4x4 system ( the rotary selector dial is located to the left and below the radio, it has 4 positions , 2H / A4WD / 4H / 4L )
In a 2001 Ford Expedition : ( both rear wheel drive and 4x4 versions were available ) * if it has the 4x4 Control Trac system the rotary selector dial is to the left and below the radio . It has A4WD , 4H , and 4L positions
Salvage yard or dealer.
I believe you pull the selector knob ( park lights , headlights etc ) towards you
IF it has a vacume actuator on the axle-maybe no Vac or 12 Volts IF IT has Locking HUBS they Freeze up from not being used---- ? sometimes ? U can go from Drive to Reverse (a few times) to free up the locking gears inside the HUBS.
With the engine running , if you are in A4WD ( automatic 4 Wheel Drive ) or 4 H , just turn the selector dial to 2 H . If you are in 4 L , with the engine running and the Expedition stopped with your foot on the brake pedal , shift the transmission to NEUTRAL , then turn the selector dial to 2 H , then put the transmission in gear or park
Depending on the year. My 98 Exp EB has the knob on the dash to change the temp in the front and the console on the roof has another knob to change temps in the back
Check owner's manual. If you don't have one copy and paste link below; www.fleet.ford.com/maintenance/owners_manuals ---------------------------------------------------------------CONTROL TRAC-AUTOMATIC FOUR-WHEEL DRIVE SYSTEM (IF EQUIPPED) Your 4x4 features a heavy-duty Control Trac system, includes a computer-operated transfer case. Coupled with a center-disconnected front axle, this unique system is interactive with the road, continually monitoring and adjusting torque delivery to the front and rear wheels to optimize vehicle control. Positions of the Control Trac system The Control Trac A4WD system functions in four modes: ² 2H position delivers power only to the rear axle. ² A4WD position delivers power to the rear axle, and the front axle when road conditions dictate the need for increased traction. ² 4H position provides mechanically locked four-wheel drive power delivery to front and rear axles. ² 4L position provides mechanically locked four-wheel drive when above average power at reduced speeds is required. P HI LO 2H 4L A4WD 4HOFF *A/C *MAX A/C REW 1FF 2 SIDE 1-2 3 FM 1 ST VOL - PUSH ON AM FM BASS TREB BAL FADE AUTOSET CLK SEEK TUNE DISCSSCAN 4 DOLBY SYSTEM EJ TAPE CDCOMP 5 SHUFFLE 6 2H 4L A4WD 4H 2H 4L A4WD 4H Driving 119 Utility and four-wheel drive vehicles are not designed for cornering at speeds as high as passenger cars any more than low-slung sports cars are designed to perform satisfactorily under off-road conditions. Avoid sharp turns or abrupt maneuvers in these vehicles. Using the Control Trac system Shifting to A4WD Move the 4WD control to A4WD at a stop or at speeds up to 88 km/h (55 mph). ² At temperatures below 0° C (32° F), shifts from 2H to A4WD or 4H should not be performed above 72 km/h (45 mph). ² Do not shift into A4WD when only the rear wheels are spinning. Shifting to 2H Move the 4WD control to 2H at any forward speed. 2H 4L A4WD 4H 2H 4L A4WD 4HDriving 120 Shifting from 4H to 4L (and 4L to 4H) 1. Bring the vehicle to a stop. 2. Depress the brake. 3. Place the gearshift in N (Neutral). 4. Move the 4WD control to the 4H (or 4L) position. Shifting from A4WD to 4H Move the 4WD control from A4WD to 4H at any forward speed. Shifting from 2H to 4H can be done at speeds up to 88 km (55 mph). 2H 4L A4WD 4H 2H 4L A4WD 4H Driving 121 Driving off-road with 4WD Your vehicle is specially equipped for driving on snow, sand, mud or other rough terrain and has operating characteristics that differ from those of other conventional vehicles. When using 4WD, maintain steering wheel control at all times, especially in rough terrain. Since sudden changes in terrain can result in abrupt steering motion, always grip the steering wheel from the outside. Do not grip the spokes. Drive cautiously to avoid vehicle damage from road debris such as rocks or stumps. Be sure to map out your route before driving in any off road area. For more information on driving off-road and proper operation of your 4WD vehicle, refer the Four Wheeling supplement in your Owner's Portfolio. Driving 122