Sirius Satellite Radio Super Duty F-450 - Manual (Page 20)

4x4 Systems
Performance
PERFORMANCE/HANDLING
This page is about:
2008 F-250/F-350/F-450
Super Duty ® Pickups
Performance/Handling
July 2007 20
Electronic Shift-on-the-fly System
• Easy-to-use rotary control switch mounted in the
instrument panel used to select drive settings,
eliminating the need to stop and back up to
unlock the front hubs
• Electric motor actually shifts the transfer case
into selected drive setting
• Front hublock selectors are marked with AUTO
and LOCK. Manual override capability lets the
driver manually LOCK hubs if preferred, but the
Pulse Vacuum Hublock (PVH) design engages the
front hubs, providing virtually silent operation
• PVH system optimizes fuel economy because all
front driveline components are disconnected at
the wheels when the system is in 2WD operation
NOTE: Both of these 4x4 systems are “part-time”
systems designed to provide enhanced traction
on reduced traction surfaces only. Operating
on normal or high-traction surfaces can result in
transfer case damage, increased tire wear and
decreased fuel economy.
4x4 Systems
Performance Specifics
Dual Rear Wheels (DRW)
• Either 4x2 or 4x4 drive system
• Increase rear traction
• Improve towing stability
• Provide increased rear axle
weight ratings
Super Duty ®
4x4 Manual
Shift Lever
Super Duty
Manual-locking
Front Hub
Super Duty
Rotary Switch
Super Duty
Automatic-locking
Front Hub with
Manual Override
Large, Responsive Braking System
• Excellent stopping distance and predictable brake performance
• Large calipers and rotors
• Vented front and rear rotors
• Four-wheel disc Anti-lock Braking System (ABS) with excellent
low-speed resolution
• Brake pad material has long life for quiet brake operation and
confident pedal feel when lightly loaded and at full GVW
Traction Control
• Optional on 4x2 and 4x4 models
• Helps improve traction or limits wheel spin on slippery or loose driving surfaces
• Reduces engine power through fuel cutoff or ignition spark control
• Uses engine torque to manage wheel spin, a more precise method than brake-
controlled traction systems
• Computes wheel spin from the differential and reduces torque to match the best
traction to the wheels for that terrain
• System may be disabled when it’s not needed
Manual Shift with Manual Locking Hubs
• Simple, reliable design that is highly regarded by
serious off-roaders
• To engage the front axle, the operator must stop,
exit the vehicle and rotate both hublock selector
knobs to the LOCK position, then the desired drive
range is selected on the transfer case
• Floor-mounted transfer case shift lever is used to
move between available drive settings:
2H (2WD), 4H (4x4 High), N (Neutral)
and 4L (4x4 Low)
• When the hublocks are returned to the FREE
position, the drive axle components do not
rotate while driving, which reduces wear and
frictional drag
F-250/F-350/F-450
SD Pickups
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