Ford F series Owner's Manual page 221

High water
Never attempt to cross water that is fast flowing
or of unknown depth.
Do not drive through flooded areas unless you
are sure that the water is below the bottom of
the wheel hubs.
If you must drive through high water, drive
slowly. You may have limited traction or wet
brakes, so allow extra stopping distance because
your vehicle will not stop as quickly as usual.
After you drive through the standing water,
apply your brakes gently several times as your
vehicle moves slowly. This helps to dry the
brakes.
NOTE: If the transmission and transfer case is
submerged in water, their fluids should
be checked and changed, if necessary.
NOTE: All rear axle lube quantities must be
replaced every 100,000 miles
(160,000 km) or if the axle has been
submerged in water. Otherwise, the
lube should not be checked or changed
unless a leak is suspected or repair
required.
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