Recommended Shift Speeds; Upshifts When Accelerating; Upshifts When Cruising - Ford 2008 F-150 Owner's Manual

Driving
5. Release the parking brake, then slowly release the clutch pedal while
slowly pressing on the accelerator.
During each shift, the clutch pedal must be fully depressed to the floor.
Make sure the floor mat is properly positioned so it doesn't interfere with
the full extension of the clutch pedal.
Failure to fully depress the clutch pedal to the floor may cause
increased shift efforts, prematurely wear transmission
components or damage the transmission.
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 economy)
Shift from:
1 - 2
2 - 3
3 - 4
4 - D (Overdrive)
Upshifts when cruising (recommended for best fuel economy)
Shift from:
1 - 2
2 - 3
3 - 4
4 - D (Overdrive)
276
2008 F-150
Owners Guide (post-2002-fmt)
USA
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)
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)