Page 249 of 400
SuperCab 4x4 (145” wheelbase)
Engine Rear axle ratio Maximum
GCWR-lb. (kg)Maximum
trailer
weight-lb. (kg)
4.6L (with 17”
tires)3.55 11700 (5307) 6200 (2812)
4.6L (with 18”
tires)3.55 11200 (5080) 5700 (2585)
4.6L (with 17”
tires)3.73 12200 (5534) 6700 (3039)
4.6L (with 18”
tires)3.73 11700 (5307) 6200 (2812)
5.4L (with 17”
tires)3.55 14000 (6350) 8400 (3810)
5.4L (with 18”
or 20” tires)3.55 13500 (6123) 7900 (3583)
5.4L (with 17”
tires)3.73 15000 (6804) 9400 (4624)
5.4L (with 18”
or 20” tires)3.73 14500 (6577) 8900 (4037)
SuperCab 4x4 (163” wheelbase)
Engine Rear axle ratio Maximum
GCWR-lb. (kg)Maximum
trailer
weight-lb. (kg)
5.4L (Heavy
Duty)4.10 15300 (6940) 9300 (4218)
2008 F-150(f12)
Owners Guide (post-2002-fmt)
USA(fus)
Tires, Wheels and Loading
249
Page 250 of 400
Crew Cab 4x2 (139” wheelbase)
Engine Rear axle ratio Maximum
GCWR-lb. (kg)Maximum
trailer
weight-lb. (kg)
4.6L (with 17”
tires)3.55 11700 (5307) 6400 (2903)
4.6L (with 18”
tires)3.55 11200 (5080) 5900 (2676)
4.6L (with 17”
tires)3.73 12200 (5534) 6900 (3130)
4.6L (with 18”
or 20” tires)3.73 11700 (5307) 6400 (2903)
5.4L (with 17”
tires)3.55 14000 (6350) 8600 (3901)
5.4L (with 18”
or 20” tires)3.55 13500 (6123) 8100 (3674)
5.4L (with 17”
tires)3.73 15000 (6804) 9500 (4309)
5.4L (with 18”
or 20” tires)3.73 14500 (6577) 9000 (4082)
Crew Cab 4x2 (139” wheelbase) Harley-Davidson & Limited
Versions
Engine Rear axle ratio Maximum
GCWR-lb. (kg)Maximum
trailer
weight-lb. (kg)
5.4L 3.73 11000 (4990) 5300 (2404)
2008 F-150(f12)
Owners Guide (post-2002-fmt)
USA(fus)
Tires, Wheels and Loading
250
Page 251 of 400
Crew Cab 4x4 (139” wheelbase)
Engine Rear axle ratio Maximum
GCWR-lb. (kg)Maximum
trailer
weight-lb. (kg)
4.6L (with 17”
tires)3.73 12200 (5534) 6600 (2994)
4.6L (with 18”
tires)3.73 11700 (5307) 6100 (2767)
5.4L (with 17”
tires)3.55 14000 (6350) 8300 (3765)
5.4L (with 18”
or 20” tires)3.55 13500 (6123) 7800 (3538)
5.4L (with 17”
tires)3.73 15000 (6804) 9300 (4445)
5.4L (with 18”
or 20” tires)3.73 14500 (6577) 8800 (3992)
Crew Cab 4x4 (139” wheelbase) Harley-Davidson & Limited
Versions
Engine Rear axle ratio Maximum
GCWR-lb. (kg)Maximum
trailer
weight-lb. (kg)
5.4L 3.73 11000 (4990) 5100 (2313)
2008 F-150(f12)
Owners Guide (post-2002-fmt)
USA(fus)
Tires, Wheels and Loading
251
Page 252 of 400
Crew Cab 4x2 (151” wheelbase)
Engine Rear axle ratio Maximum
GCWR-lb. (kg)Maximum
trailer
weight-lb. (kg)
4.6L (with 17”
tires)3.55 11700 (5307) 6300 (2858)
4.6L (with 18”
tires)3.55 11200 (5080) 5800 (2631)
4.6L (with 17”
tires)3.73 12200 (5534) 6800 (3084)
4.6L (with 18”
or 20” tires)3.73 11700 (5307) 6300 (2858)
5.4L (with 17”
tires)3.55 14000 (6350) 8500 (3855)
5.4L (with 18”
or 20” tires)3.55 13500 (6123) 8000 (3629)
5.4L (with 17”
tires)3.73 15000 (6804) 9500 (4309)
5.4L (with 18”
or 20” tires)3.73 14500 (6577) 9000 (4082)
2008 F-150(f12)
Owners Guide (post-2002-fmt)
USA(fus)
Tires, Wheels and Loading
252
Page 253 of 400

Crew Cab 4x4 (151” wheelbase)
Engine Rear axle ratio Maximum
GCWR-lb. (kg)Maximum
trailer
weight-lb. (kg)
4.6L (with 17”
tires)3.73 12200 (5534) 6600 (2994)
4.6L (with 18”
tires)3.73 11700 (5307) 6100 (2767)
5.4L (with 17”
tires)3.55 14000 (6350) 8200 (3719)
5.4L (with 18”
or 20” tires)3.55 13500 (6123) 7700 (3493)
5.4L (with 17”
tires)3.73 15000 (6804) 9200 (4173)
5.4L (with 18”
or 20” tires)3.73 14500 (6577) 8700 (3946)
Trailer frontal area considerations:
•Not to exceed towing vehicle frontal area without Class IV trailer
towing package
•Not to exceed 60 square feet (5.52 square meters) with Class IV
trailer towing package
Note:Do not exceed trailer weight of 5,000 lb (2268 kg) when towing
with bumper only.
Preparing to tow
Use the proper equipment for towing a trailer and make sure it is
properly attached to your vehicle. See your authorized dealer or a
reliable trailer dealer if you require assistance.
Hitches
Do not use hitches that clamp onto the vehicle’s bumper or attach to the
axle. You must distribute the load in your trailer so that 10%–15% of the
total weight of the trailer is on the tongue.
2008 F-150(f12)
Owners Guide (post-2002-fmt)
USA(fus)
Tires, Wheels and Loading
253
Page 256 of 400

Trailer towing tips
•Practice turning, stopping and backing up before starting on a trip to
get the feel of the vehicle trailer combination. When turning, make
wider turns so the trailer wheels will clear curbs and other obstacles.
•Allow more distance for stopping with a trailer attached.
•The trailer tongue weight should be 10–15% of the loaded trailer
weight.
•If you will be towing a trailer frequently in hot weather, hilly
conditions, at GCWR, or any combination of these factors, consider
refilling your rear axle with synthetic gear lube if not already so
equipped. Refer to theMaintenance and specificationschapter for
the lubricant specification. Remember that regardless of the rear axle
lube used, do not tow a trailer for the first 1,000 miles (1600 km) of a
new vehicle, and that the first 500 miles (800 km) of towing be done
at no faster than 70 mph (112 km/h) with no full throttle starts.
•After you have traveled 50 miles (80 km), thoroughly check your
hitch, electrical connections and trailer wheel lug nuts.
•To aid in engine/transmission cooling and A/C efficiency during hot
weather while stopped in traffic, place the gearshift lever in P (Park)
(automatic transmission) or N (Neutral) (manual transmissions).
•Vehicles with trailers should not be parked on a grade. If you must
park on a grade, place wheel chocks under the trailer’s wheels.
Launching or retrieving a boat
Disconnect the wiring to the trailer before backing the trailer
into the water. Reconnect the wiring to the trailer after the
trailer is removed from the water.
When backing down a ramp during boat launching or retrieval:
•do not allow the static water level to rise above the bottom edge of
the rear bumper.
•do not allow waves to break higher than 6 inches (15 cm) above the
bottom edge of the rear bumper.
Exceeding these limits may allow water to enter vehicle components:
•causing internal damage to the components.
•affecting driveability, emissions and reliability.
Replace the rear axle lubricant any time the axle has been submerged in
water. Rear axle lubricant quantities are not to be checked or changed
unless a leak is suspected or repair required.
2008 F-150(f12)
Owners Guide (post-2002-fmt)
USA(fus)
Tires, Wheels and Loading
256
Page 258 of 400

STARTING
Positions of the ignition
1. OFF/LOCK, locks the steering
wheel, automatic transmission
gearshift lever and allows key
removal.
Note:The ignition key cannot be
removed from the ignition unless
the gearshift lever is securely
latched in P (Park).
2. ACCESSORY, allows the electrical
accessories such as the radio to
operate while the engine is not running.
3. ON, all electrical circuits operational. Warning lights illuminated. Key
position when driving.
4. START, cranks the engine. Release the key as soon as the engine
starts.
Preparing to start your vehicle
Engine starting is controlled by the powertrain control system. This
system meets all Canadian Interference-Causing Equipment standard
requirements regulating the impulse electrical field strength of radio
noise.
When starting a fuel-injected engine, don’t press the accelerator before
or during starting. Only use the accelerator when you have difficulty
starting the engine. For more information on starting the vehicle, refer to
Starting the enginein this chapter.
Extended idling at high engine speeds can produce very high
temperatures in the engine and exhaust system, creating the risk
of fire or other damage.
Do not park, idle, or drive your vehicle in dry grass or other dry
ground cover. The emission system heats up the engine
compartment and exhaust system, which can start a fire.
2008 F-150(f12)
Owners Guide (post-2002-fmt)
USA(fus)
Driving
258
Page 259 of 400

Do not start your vehicle in a closed garage or in other enclosed
areas. Exhaust fumes can be toxic. Always open the garage door
before you start the engine. SeeGuarding against exhaust fumesin
this chapter for more instructions.
If you smell exhaust fumes inside your vehicle, have your dealer
inspect your vehicle immediately. Do not drive if you smell
exhaust fumes.
Important safety precautions
A computer system controls the engine’s idle revolutions per minute
(RPM). When the engine starts, the idle RPM runs higher than normal in
order to warm the engine. If the engine idle speed does not slow down
automatically, have the vehicle checked. If the vehicle is operated in a
heavy snow storm or blowing snow conditions, the engine air induction
may become partially clogged with snow and/or ice. If this occurs the
engine may experience a significant reduction in power output. At the
earliest opportunity, clear all snow and/or ice away from the air induction
inlet. Do not allow the vehicle to idle for more than 10 minutes at the
higher engine RPM.
Before starting the vehicle:
1. Make sure all vehicle occupants have buckled their safety belts. For
more information on safety belts and their proper usage, refer to the
Seating and Safety Restraintschapter.
2. Make sure the headlamps and vehicle accessories are off.
If starting a vehicle with an automatic transmission:
•Make sure the gearshift is in
P (Park).
2008 F-150(f12)
Owners Guide (post-2002-fmt)
USA(fus)
Driving
259