Ford F series Owner's Manual page 217

Do not exceed the GVWR or the GAWR
specified on the Safety Compliance
Certification Label.
Vehicle Operation On the Road
When operating on the road, your engine may
run at a temperature higher than normal because
the attached snowplow blade will restrict airflow
to the radiator. So if you are driving more than
15 continuous miles (24 km), at temperatures
above freezing, angle the plow blade either full
left or full right to provide maximum airflow to
the radiator. Shorter trips of 15 miles (24 km) in
cold weather may be made at speeds up to
40 mph (64 km/h) without paying special
attention to plow blade position.
Vehicle Operation While Plowing
Guard against transmission and drivetrain
damage. When plowing small areas or heavy
snow, operate with the transfer case in 4L and a
vehicle speed of 0-5 mph (8 km/h). When
plowing larger areas or light snow, at higher
speeds, operate with the transfer case in 4H and
do not exceed 15 mph (24 km/h).
Do not shift the transmission from forward to
reverse until the engine is at idle and the wheels
are stopped.
RWARNING
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