Ford Navigator 2012 Owner's Manual page 367

SPECIAL OPERATING CONDITIONS
If you operate your vehicle primarily in one of the more demanding
conditions listed below, you will need to have some items maintained
more frequently. If you only occasionally operate your vehicle under
these conditions, it is not necessary to perform the additional
maintenance. For specific recommendations, see your dealership service
advisor or technician.
Towing a trailer or using a camper or car-top carrier
Inspect frequently, Inspect and lubricate U-joints
service as required
See axle maintenance items under Exceptions
Every 5,000 miles Inspect wheels and related components for
(8,000 km) abnormal noise, wear, looseness or drag
Rotate tires*, inspect tire wear and measure
tread depth
Every 5,000 miles Change engine oil and filter
(8,000 km) or
Inspect and lubricate U-joints
6 months
Every 30,000 miles Change automatic transmission fluid (except
(48,000 km) 6R80 and TorqShift transmissions)
Replace front wheel bearing grease/grease seals if
non-sealed bearings are used (2WD vehicles)
Every 60,000 miles Change manual transmission fluid
(96,000 km)
Change transfer case fluid (4WD vehicles)
*If equipped with dual rear wheels, rotate front wheels when specified,
rear wheels only if unusual wear is noted
2012 Navigator (nav)
Owners Guide, 1st Printing
USA (fus)
Scheduled Maintenance
367