Ford F-150 Owner's Manual page 294

Driving
• Some noise is normal during operation. If excessive, check for low
power steering pump fluid level before seeking service by your
authorized dealer.
• Heavy or uneven steering efforts may be caused by low power steering
pump fluid level. Check for low power steering pump fluid level before
seeking service by your authorized dealer.
• Do not fill the power steering pump reservoir above the MAX mark on
the reservoir, as this may result in leaks from the reservoir.
All engines
If the steering wanders or pulls equipped with either an EPS or a
hydraulic steering system, check for:
• an improperly inflated tire
• uneven tire wear
• loose or worn suspension components
• loose or worn steering components
• improper steering alignment
A high crown in the road or high crosswinds may also make the steering
seem to wander/pull.
LIMITED-SLIP AXLE (IF EQUIPPED)
This axle provides added traction on slippery surfaces, particularly when
one wheel is on a poor traction surface. Under normal conditions, the
limited-slip axle functions like a standard rear axle. The axle may exhibit
a slight noise or vibration in tight turns with low vehicle speed. This is
normal behavior and indicates the axle is working.
Electronic locking differential (ELD) (if equipped)
The electronic locking differential provides added traction on slippery
and/or off-road surfaces, particularly when one wheel is on a poor
traction surface. In normal driving conditions, the rear axle functions as
a standard axle. The ELD may be locked or unlocked by the vehicle
operator. Refer to Four-wheel drive (4WD) operation section in this
chapter for further details on ELD function and usage. When the axle is
unlocked, it will function like a standard rear axle. When the axle is
locked, it will not allow the rear wheels to rotate at different speeds
when turning. The ELD axle is not recommended for use on good
traction surfaces such as dry pavement. Doing so may result in abnormal
driving behavior while cornering and excessive tire wear.
294
2011 F-150 (f12)
Owners Guide, 3rd Printing
USA (fus)