Honda Ridgeline Owner's Manual page 342

Automatic Transmission Fluid
DIPSTICK
UPPER MARK
LOWER MARK
3. Insert the dipstick all the way into
the transmission securely as
shown in the illustration.
4. Remove the dipstick and check
the fluid level. It should be
between the upper and lower
marks.
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5. If the level is below the lower
mark, remove the fill plug, then
add the fluid into the fill hole to
bring it to the level between the
upper and lower marks on the
dipstick.
Pour the fluid slowly and carefully so
you do not spill any. Clean up any
spill immediately; it could damage
components in the engine
compartment.
Always use Honda ATF DW-1
(automatic transmission fluid).
Use only Honda ATF DW-1 (automatic
transmission f luid). Do not mix with
other transmission f luids.
Using transmission f luid other than
Honda ATF DW-1 may cause
deterioration in transmission operation
and durability, and could result in
damage to the transmission.
Damage resulting f rom the use of
transmission f luid other than Honda
ATF DW-1 is not covered by the Honda
new vehicle warranty.
6. Insert the dipstick all the way back
in the transmission.
If you are not sure how to add fluid,
contact your dealer.