Page 305 of 571

TRANSMISSION FLUID CHECK
6F50/6F55 Transmission
WARNING:The dipstick cap and surrounding components may
be hot; gloves are recommended.
WARNING:Use gloves when moving the air filter assembly;
components will be hot.
Note:Automatic transmission fluid expands when warmed. To obtain an
accurate fluid check, drive the vehicle until it is warmed up (approximately
20 miles [30 km]). If your vehicle has been operated for an extended
period at high speeds, in city traffic during hot weather or pulling a trailer,
the vehicle should be turned off until normal operating temperatures are
reached to allow the fluid to cool before checking. Depending on vehicle
use, cooling times could take up to 30 minutes or longer.
Refer to yourscheduled maintenance informationfor scheduled
intervals for fluid checks and changes. Your transmission does not
consume fluid. However, the fluid level should be checked if the
transmission is not working properly, i.e., if the transmission slips or
shifts slowly or if you notice some sign of fluid leakage.
1. Drive the vehicle 20 miles (30 km) or until it reaches normal operating
temperature.
2. Park the vehicle on a level surface and engage the parking brake.
3. With the parking brake engaged and your foot on the brake pedal,
start the engine and move the gearshift lever through all of the gear
ranges. Allow a minimum of 10 seconds for each gear to engage.
4. Latch the gearshift lever inP(Park) and leave the engine running.
5. Remove the dipstick, wiping it clean with a clean, dry lintfree rag. If
necessary, refer toUnder hood overviewin this chapter for the location
of the dipstick. (For vehicles with the EcoBoost engine, move the air
filter assembly aside to access the transmission dipstick. SeeMoving the
Air Filter Assembly (EcoBoost engine)for more information.
6. Install the dipstick making sure it is fully seated in the filler tube by
turning it to the locked position.
7. Remove the dipstick and inspect the fluid level. The fluid should be in
the designated areas for normal operating temperature.
304Maintenance
2015 Flex(471)
Owners Guide gf, 1st Printing, October 2014
USA(fus)
Page 306 of 571
Moving the Air Filter Assembly (EcoBoost engine)
WARNING:Do not run engine with the air filter disconnected.
1. Shut the engine off.
2. Clean the area around the clamp
that connects the air filter assembly
to the rubber hose (1).
3. Remove the bolt cover (if
equipped).
4. Remove two bolts that attach the air filter assembly to the front of the
vehicle (2).
5. Loosen the clamp holding the air filter assembly to the rubber hose (1).
6. Remove the harness retaining clip by pulling up (3). Do not
disconnect the sensor (4).
Maintenance305
2015 Flex(471)
Owners Guide gf, 1st Printing, October 2014
USA(fus)
Page 307 of 571

7. Without disconnecting the sensor (4), pull the air filter assembly up to
disconnect the air filter assembly from the seated grommets located
underneath the air filter assembly.
8. Rotate the air filter assembly 90
degrees counterclockwise and
reinstall into the rubber hose.
9. Tighten the clamp (1).
10. The transmission fluid level indicator can now be accessed.
Low fluid level
If the fluid level is below the MIN
range of the dipstick, add fluid to
reach the hash mark level.Note:If
the fluid level is below the MIN level,
do not drive the vehicle. An underfill condition may cause shift and/or
engagement concerns and/or possible damage.
Correct fluid level
The transmission fluid should be checked at normal operating
temperature 180°F-200°F (82°C-93°C) on a level surface. The normal
operating temperature can be reached after approximately 20 miles
(30 km) of driving.
The transmission fluid level should be
targeted within the cross-hatch area
if at normal operating temperature
180°F-200°F (82°C-93°C).
MAX MIN
306Maintenance
2015 Flex(471)
Owners Guide gf, 1st Printing, October 2014
USA(fus)
Page 308 of 571

High fluid level
If the fluid level is above the MAX
range of the dipstick, remove fluid to
reach the hashmark level.Note:
Fluid level above the MAX level may
cause shift and/or engagement concerns and/or possible damage.
High fluid levels can be caused by an overheating condition. If your
vehicle has been operated for an extended period at high speeds, in city
traffic during hot weather or pulling a trailer, the vehicle should be
turned off until normal operating temperatures are reached. Depending
on vehicle use, cooling times could take up to 30 minutes or longer.
Adjusting Automatic Transmission Fluid Levels
Before adding any fluid, make sure the correct type is used. The type of
fluid used is normally indicated on the dipstick and also in theTechnical
specificationssection in this chapter.
Note:Use of a non-approved automatic transmission fluid may cause
internal transmission component damage.
If necessary, add fluid in 1/2 pint
(250 ml) increments through the
filler tube until the level is correct.
If an overfill occurs, excess fluid
should be removed by an authorized
dealer.
Note:An overfill condition of transmission fluid may cause shift and/or
engagement concerns and/or possible damage.
Do not use supplemental transmission fluid additives, treatments or
cleaning agents. The use of these materials may affect transmission
operation and result in damage to internal transmission components.
For vehicles equipped with the EcoBoost engine, reinstall the air filter
assembly.
After the fluid level has been checked and adjusted as necessary, do the
following:
1. Shut the engine off.
2. Loosen the clamp holding the air filter assembly to the rubber hose.
3. Rotate the air filter assembly 90 degrees clockwise without
disconnecting the sensor.
MAX MIN
MAX MIN
Maintenance307
2015 Flex(471)
Owners Guide gf, 1st Printing, October 2014
USA(fus)
Page 309 of 571

4. Seat the air filter assembly back into the grommets by pushing down
on the air filter assembly.
5. Tighten the clamp.
6. Install and tighten two bolts that attach air filter assembly to the front
of the vehicle.
7. Install the bolt cover (if equipped).
8. Reinstall the harness retaining clip into the front of the air filter assembly.
BRAKE FLUID CHECK
Fluid levels between the MIN and MAX lines are within the normal
operating range; there is no need to add fluid. If the fluid levels are outside
of the normal operating range, the performance of the system could be
compromised; seek service from your authorized dealer immediately.
POWER STEERING FLUID CHECK
Your vehicle is equipped with an electric power steering (EPS) system.
There is no fluid reservoir to check or fill. For additional information on
the electric power steering (EPS) system, Refer toDriving Aids.
FUEL FILTER
Your vehicle is equipped with a lifetime fuel filter that is integrated with
the fuel tank. Regular maintenance or replacement is not needed.
WASHER FLUID CHECK
WARNING:If you operate your vehicle in temperatures below 40°F
(5°C), use washer fluid with antifreeze protection. Failure to use
washer fluid with antifreeze protection in cold weather could result in
impaired windshield vision and increase the risk of injury or accident.
Add fluid to fill the reservoir if the level is low. Only use a washer fluid
that meets Ford specifications. See the technical specifications chart in
theCapacities and Specificationschapter.
Note:The front and rear washer systems are supplied from the same
reservoir.
State or local regulations on volatile organic compounds may restrict the
use of methanol, a common windshield washer antifreeze additive.
Washer fluids containing non-methanol antifreeze agents should be used
only if they provide cold weather protection without damaging the
vehicle’s paint finish, wiper blades or washer system.
308Maintenance
2015 Flex(471)
Owners Guide gf, 1st Printing, October 2014
USA(fus)
Page 310 of 571

CHANGING THE VEHICLE BATTERY
WARNING:Batteries normally produce explosive gases which
can cause personal injury. Therefore, do not allow flames, sparks
or lighted substances to come near the battery. When working near the
battery, always shield your face and protect your eyes. Always provide
proper ventilation.
WARNING:When lifting a plastic-cased battery, excessive
pressure on the end walls could cause acid to flow through the
vent caps, resulting in personal injury and damage to the vehicle or
battery. Lift the battery with a battery carrier or with your hands on
opposite corners.
WARNING:Keep batteries out of reach of children. Batteries
contain sulfuric acid. Avoid contact with skin, eyes or clothing.
Shield your eyes when working near the battery to protect against
possible splashing of acid solution. In case of acid contact with skin or
eyes, flush immediately with water for a minimum of 15 minutes and
get prompt medical attention. If acid is swallowed, call a physician
immediately.
WARNING:Battery posts, terminals and related accessories
contain lead and lead compounds. Wash hands after handling.
Your vehicle is equipped with a Motorcraft® maintenance-free battery
which normally does not require additional water during its life of service.
Note:If your battery has a cover or a shield, make sure it is reinstalled
after the battery has been cleaned or replaced.
For longer, trouble-free operation, keep the top of the battery clean and
dry. Also, make certain the battery cables are always tightly fastened to
the battery terminals.
If you see any corrosion on the battery or terminals, remove the cables
from the terminals and clean with a wire brush. You can neutralize the
acid with a solution of baking soda and water.
It is recommended that the negative battery cable terminal be
disconnected from the battery if you plan to store your vehicle for an
extended period of time.
Maintenance309
2015 Flex(471)
Owners Guide gf, 1st Printing, October 2014
USA(fus)
Page 311 of 571

Battery relearn
Because your vehicle’s engine is electronically controlled by a computer,
some control conditions are maintained by power from the battery. When
the battery is disconnected or a new battery is installed, the engine must
relearn its idle and fuel trim strategy for optimum driveability and
performance. To begin this process:
1. With the vehicle at a complete stop, set the parking brake.
2. Put the gearshift lever inP(Park), turn off all accessories and start
the engine.
3. Run the engine until it reaches normal operating temperature.
4. Allow the engine to idle for at least one minute.
5. Turn the A/C on and allow the engine to idle for at least one minute.
6. Drive the vehicle to complete the relearning process.
•The vehicle may need to be driven to relearn the idle and fuel trim
strategy.
•Note:If you do not allow the engine to relearn its idle trim, the idle
quality of your vehicle may be adversely affected until the idle trim is
eventually relearned.
When the battery is disconnected or a new battery installed, the
transmission must relearn its adaptive strategy. As a result of this, the
transmission may shift firmly. This operation is considered normal and
will not affect function or durability of the transmission. Over time the
adaptive learning process will fully update transmission operation to its
optimum shift feel.
If the battery has been disconnected or a new battery has been installed,
the clock and the preset radio stations must be reset once the battery is
reconnected.
Always dispose of automotive batteries in a responsible manner. Follow
your local authorized standards for disposal. Call your local authorized
recycling center to find out more about recycling automotive batteries.
310Maintenance
2015 Flex(471)
Owners Guide gf, 1st Printing, October 2014
USA(fus)
Page 312 of 571

CHECKING THE WIPER BLADES
Run the tip of your fingers over the edge of the blade
to check for roughness.
Clean the wiper blades with washer fluid or water
applied with a soft sponge or cloth.
CHANGING THE WIPER BLADES
1. Pull the wiper arm away from the
vehicle. Turn the blade at an angle
from the wiper arm. Press the lock
tab to release the blade and pull the
wiper blade down toward the
windshield to remove it from the arm.
2. Attach the new wiper to the wiper
arm and press it into place until a
click is heard.
Replace wiper blades at least once per year for optimum performance.
Poor wiper quality can be improved by cleaning the wiper blades and the
windshield.
To prolong the life of the wiper blades, it is highly recommended to
scrape off the ice on the windshield before turning on the wipers. The
layer of ice has many sharp edges and can damage the micro edge of the
wiper rubber element.
Changing rear window wiper blade
To replace the rear wiper blade:
1. Grab the wiper arm with one
hand close to the arm/blade joint
and pull it as far away from the
glass as possible. Do not use
excessive force because it can break
the wiper arm at the heel. Hold it
there until the next step.
Maintenance311
2015 Flex(471)
Owners Guide gf, 1st Printing, October 2014
USA(fus)