Ford Super Duty (2017 year). Manual — part 54

LIMITED SLIP DIFFERENTIAL

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
during tight turns with low vehicle speed.
This is normal behavior and indicates the
axle is working.

ELECTRONIC LOCKING
DIFFERENTIAL

(If Equipped)

Note: The electronic locking differential is
for off-road use only and is not for use on
dry pavement. Using the electronic locking
differential on dry pavement will result in
increased tire wear, noise and vibration.

The electronic locking differential is a
device housed in the rear axle that allows
both rear wheels to turn at the same
speed. The electronic locking differential
can provide additional traction should your
vehicle become stuck. You can activate
the differential electronically and shift it
on the fly within the differential operating
speed range. The differential is for use in
mud, rocks, sand, or any off-road condition
where you need maximum traction. It is
not for use on dry pavement.

The following conditions will affect the
electronic locking differential:

•

The electronic locking differential will
not engage if your vehicle speed is
above 20 mph (32 km/h) in 4x2, 4x4
Auto, or 4x4 High modes.

•

The electronic locking differential will
not engage if your vehicle speed is
above or 56 mph (90 km/h) in 4X4
Low.

•

The electronic locking differential may
not engage if you press your
accelerator pedal during an
engagement attempt. A message may
display in the instrument display
guiding you to release the accelerator
pedal.

•

In 4x2, 4x4 Auto, and 4x4 High modes,
the electronic locking differential will
automatically disengage at speeds
above 25 mph (41 km/h) and will
automatically reengage at speeds
below 20 mph (32 km/h).

•

In 4L (4X4 low), the electronic locking
differential will automatically
disengage at speeds above 62 mph
(100 km/h) and will automatically
reengage at speeds below 56 mph
(90 km/h).

•

The AdvanceTrac system has the
ability to take over control of the
electronic locking differential and
disable it during driving maneuvers
when necessary.

When you switch the system on, if you do
not meet the required conditions for
electronic locking differential activation,
the instrument cluster will display the
appropriate information guiding you
through the proper activation process.

Activating the Electronic Locking
Differential

Note: Do not use electronic locking
differential on dry, hard surfaced roads.
Doing so will produce excessive noise,
vibration and increase tire wear.

Note: If the electronic locking differential
has difficulty disengaging, release the
accelerator pedal and turn the steering
wheel in the opposite direction while rolling.

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For 4WD vehicles

E191852

Pull the 4WD control knob toward you.

For 2WD vehicles

E183740

Turn the control to ON.

E163170

Once the indicator light
illuminates in the information
display, both rear wheel axle

shafts will be locked together providing
added traction.

If the indicator does not come on, or the
indicator turns off while driving, one of the
following has occurred:

•

The vehicle speed is too high.

•

The left and right rear wheel speed
difference is too high during an
engagement attempt.

•

The system has malfunctioned and is
accompanied by CHECK LOCKING
DIFFERENTIAL in the information
display. See your authorized Ford
dealer for assistance.

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GENERAL INFORMATION

Note: Occasional brake noise is normal. If
a metal-to-metal, continuous grinding or
continuous squeal sound is present, the
brake linings may be worn-out. Have the
system checked by an authorized dealer. If
your vehicle has continuous vibration or
shudder in the steering wheel while braking,
have it checked by an authorized dealer.

Note: Brake dust may accumulate on the
wheels, even under normal driving
conditions. Some dust is inevitable as the
brakes wear and does not contribute to
brake noise. See Cleaning the Wheels
(page 366).

E144522

See Warning Lamps and
Indicators (page 105).

Wet brakes result in reduced braking
efficiency. Gently press the brake pedal a
few times when driving from a car wash or
standing water to dry the brakes.

Brake Over Accelerator

In the event the accelerator pedal
becomes stuck or entrapped, apply steady
and firm pressure to the brake pedal to
slow the vehicle and reduce engine power.
If you experience this condition, apply the
brakes and bring your vehicle to a safe
stop. Move the transmission to park (P),
switch the engine off and apply the parking
brake. Inspect the accelerator pedal for
any interference. If none are found and the
condition persists, have your vehicle towed
to the nearest authorized dealer.

Brake Assist

Brake assist detects when you brake
rapidly by measuring the rate at which you
press the brake pedal. It provides
maximum braking efficiency as long as you
press the pedal, and can reduce stopping
distances in critical situations.

Anti-lock Brake System

This system helps you maintain steering
control during emergency stops by keeping
the brakes from locking.

This lamp momentarily
illuminates when you switch the
ignition on. If the light does not

illuminate during start up, remains on or
flashes, the system may be disabled. Have
the system checked by an authorized
dealer. If the anti-lock brake system is
disabled, normal braking is still effective.

E144522

If the brake warning lamp
remains illuminated after you
release the parking brake, have

the system checked by an authorized
dealer.

Diesel Engine Braking

(If Equipped)

WARNING

Do not use tow/haul or engine
braking when driving in icy or slippery
conditions as the increased braking

can cause the rear wheels to slide and your
vehicle to swing around with the possible
loss of vehicle control.

This feature increases engine braking at
higher engine speeds to provide better
grade descent control with less brake and
transmission wear and tear. It also
improves engine braking when towing or
carrying heavy loads.

E171217

Press the button on the switch
bank next to the audio unit to
switch the system on or off.

There are two engine brake modes, manual
and automatic.

Manual Engine Braking

1.

Press the button to switch on manual
engine braking.

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2. Release the accelerator pedal to

maximize engine braking.

3. Apply the brakes. The transmission

downshifts to lower gears.

Note: You can shift the transmission to
lower gears with progressive range selection
(PRS) or manual shifting independent of
pressing the brakes.

Note: You can also use manual engine
braking with cruise control to improve grade
descent control.

Automatic Engine Braking

1.

Press the button twice to switch on
automatic engine braking.

2. Release the accelerator or brake pedal.

The system remembers your vehicle
speed.

Note: The system automatically activates
the engine brake and, if necessary,
downshifts the transmission to lower gears
to not exceed your vehicle's set speed when
the brake or accelerator were last released.

Note: Use this when driving downhill and
carrying heavy loads or trailering.

Warning Lamp Conditions

•

Illuminates when this feature is
switched on and the system is
operating properly. See Warning
Lamps and Indicators (page 105).

•

Flashes when the engine brake is
disabled due to a fault or the engine
does not meet the required braking
conditions.

•

Does not illuminate when the switch
or indicator is faulty.

You can switch the system on at anytime.
The system becomes active once the
braking conditions are met.

Braking Conditions

•

Your vehicle is in a forward gear.

•

The engine speed is above about 1500
RPM.

•

Your foot is off the accelerator.

You can use this feature with tow/haul or
progressive range selection to provide
further increased engine braking. The
transmission automatically upshifts to
prevent the engine from entering the red
zone on the tachometer. See Automatic
Transmission (page 205).

HINTS ON DRIVING WITH
ANTI-LOCK BRAKES

Note: When the system is operating, the
brake pedal may pulse and may travel
further. Maintain pressure on the brake
pedal. You may also hear a noise from the
system. This is normal.

The anti-lock braking system will not
eliminate the risks when:
•

You drive too closely to the vehicle in
front of you.

•

Your vehicle is hydroplaning.

•

You take corners too fast.

•

The road surface is poor.

PARKING BRAKE

WARNING

Always set the parking brake fully
and make sure the transmission is
placed in park (P). Failure to set the

parking brake and engage park could result
in vehicle roll-away, property damage or
bodily injury. Turn the ignition to the lock
position and remove the key whenever you
leave your vehicle.

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