FORD 2015 F-550 v.1 - Manual (Page 450)

Off-road operation
Inspect steering linkage, ball joints and U-joints, Lubricate
if equipped with grease fittings. Inspect frequently, service
as required
Replace engine air filter.
Change engine oil and filter. Every 5000 miles (8000
km) or six months
Inspect the wheels and related components for abnormal
noise, wear, looseness or drag.
Rotate tires * , inspect tires for wear and measure tread
depth.
Replace front wheel bearing grease and grease seals if
non-sealed bearings are used. Every 30000 miles (48000
km)
Change rear axle fluid (F-450 and F-550 only). Every 50000 miles (80000
km)
Change transfer case fluid (Four-wheel drive vehicles). Every 60000 miles (96000
km)
* Vehicles with dual rear wheels should rotate the front wheels when specified; rear wheels
only if unusual wear is noted.
Exclusive use of E85 (Flex fuel vehicles only)
If ran exclusively on E85, fill the fuel tank full with regular
unleaded fuel. Every oil change interval
6.7L Diesel Engine
See the diesel supplement for special
operating condition information.
Exceptions
There are several exceptions to the Normal
Schedule:
Axle Maintenance
Change the axle fluid anytime an axle is
submerged in water.
Rear axles and power take-off units with
synthetic fluid and light-duty trucks
equipped with Ford-design axles are
lubricated for life; do not check or change
fluid unless a leak is suspected, service is
required or the assembly has been
submerged in water. During long periods
of trailer towing with outside temperatures
above 70°F (21°C) and at wide-open
throttle for long periods above 45 mph (72
km/h), change non-synthetic rear axle fluid
every 3000 miles (4800 kilometers) or
three months, whichever comes first. This
interval can be waived if the axle is filled
with 75W140 synthetic gear fluid meeting
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Super Duty (), enUSA
Scheduled Maintenance