Ford F-150 Owner's Manual page 216

Driving
During each shift, the clutch pedal must be fully depressed to the floor.
Failure to fully depress the clutch pedal to the floor may cause increased
shift efforts, prematurely wear transmission components or damage the
transmission. Make sure the floor mat is properly positioned so it doesn't
interfere with the full extension of the clutch pedal.
Do not drive with your foot resting on the clutch pedal or use the clutch
pedal to hold your vehicle at a standstill while waiting on a hill. These
actions will reduce the life of the clutch.
Recommended shift speeds
Upshift and downshift according to the following charts for your specific
engine/drivetrain combination:
Upshifts when accelerating (recommended for best fuel
Shift from:
1 - 2
2 - 3
3 - 4
4
- (Overdrive)
D
Upshifts when cruising (recommended for best fuel economy)
Shift from:
1 - 2
2 - 3
3 - 4
4
- (Overdrive)
D
Maximum downshift speeds
Shift from:
(Overdrive) -
D
4
216
2006 F-150 (f12)
Owners Guide (post-2002-fmt)
USA (fus)
economy)
Transfer case position (if equipped)
2H or 4H
15 mph (24 km/h)
25 mph (40 km/h)
37 mph (60 km/h)
45 mph (72 km/h)
Transfer case position (if equipped)
2H or 4H
11 mph (18 km/h)
21 mph (34 km/h)
31 mph (50 km/h)
43 mph (69 km/h)
Transfer case position (if equipped)
2H or 4H
55 mph (89 km/h)
4L
9 mph (14 km/h)
12 mph (19 km/h)
15 mph (24 km/h)
18 mph (29 km/h)
4L
5 mph (8 km/h)
11 mph (18 km/h)
14 mph (23 km/h)
17 mph (27 km/h)
1
4L
21 mph (34 km/h)