Ford F-150 2000 Introduction Manual page 217

Maintenance and care
Checking and adding transfer case fluid (if equipped)
1. Clean the filler plug.
2. Remove the filler plug and
inspect the fluid level.
3. Add only enough fluid through
the filler opening so that the fluid
level is at the bottom of the
opening.
Use only fluid that meets Ford specifications. Refer to the Capacities
and specifications chapter.
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