UNDER HOOD OVERVIEW - 7.3L
Engine compartment fuse box. See Fuses (page 202).A
Engine oil dipstick. See Engine Oil Dipstick (page 227).B
Windshield washer fluid reservoir. See Washer Fluid Check (page 249).C
Automatic transmission fluid dipstick. See Automatic Transmission FluidCheck (page 243).D
Engine coolant reservoir. See Engine Coolant Check (page 238).E
Engine oil filler cap. See Engine Oil Check (page 227).F
Brake fluid reservoir. See Brake Fluid Check (page 245).G
Power steering fluid reservoir. See Power Steering Fluid Check (page 246).H
Air cleaner assembly. See Changing the Engine Air Filter (page 232).I
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At this time, you may notice the coolanttemperature gauge moves toward the redzone and a message may appear in theinformation display.
You may notice a reduction in vehiclespeed caused by reduced engine power inorder to manage the engine coolanttemperature. Your vehicle may enter thismode if certain high-temperature andhigh-load conditions take place. Theamount of speed reduction depends onvehicle loading, grade and ambienttemperature. If this occurs, there is noneed to pull off the road. You can continueto drive your vehicle.
The air conditioning may turn on and offduring severe operating conditions toprotect the engine from overheating. Whenthe coolant temperature decreases to thenormal operating temperature, the airconditioning turns on.
If the coolant temperature gauge movesfully into the red zone, or if the coolanttemperature warning or service enginesoon messages appear in your informationdisplay, do the following:
1.Pull off the road as soon as safelypossible and shift the transmission intopark (P).
2.Leave the engine running until thecoolant temperature gauge needlereturns to the normal position. Afterseveral minutes, if the temperaturedoes not drop, follow the remainingsteps.
3.Switch the engine off and wait for it tocool. Check the coolant level.
4.If the coolant level is at or below theminimum mark, add prediluted coolantimmediately.
5.If the coolant level is normal, restartthe engine and continue.
AUTOMATIC TRANSMISSION
FLUID CHECK
The transmission does not consume fluid.However, check the fluid level if thetransmission is not working properly, forexample if the transmission slips, shiftsslowly or if there are signs of fluid loss.
Replace the transmission fluid and filteron your vehicle at the specified serviceinterval. See Scheduled Maintenance(page 325).
Automatic transmission fluid expandswhen warmed. To check the fluid levelconsistently and accurately, do thefollowing:
1.Drive the vehicle until it reaches normaloperating temperature. This may takeup to 20 mi (30 km). Make sure thatthe transmission fluid temperaturegauge on the instrument cluster iswithin normal operating temperature196–215°F (91–102°C) beforechecking.
2.Make sure that your vehicle is on levelground.
3.With the engine running, parking brakeengaged and your foot on the brakepedal, move the gearshift lever throughall of the gear ranges. Allow sufficienttime for each gear to engage.
4.Make sure the parking brake is on. Makesure the transmission is in park (P) orneutral (N) and leave the enginerunning.
5.Open the hood. See Opening andClosing the Hood (page 223).
6.Remove the dipstick and wipe it witha clean, lint-free cloth. See UnderHood Overview (page 225).
7.Replace the dipstick and remove itagain to check the fluid level.
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BRAKE FLUID CHECK
WARNING: Do not use any fluidother than the recommended brake fluidas this will reduce brake efficiency. Useof incorrect fluid could result in the lossof vehicle control, serious personal injuryor death.
WARNING: Only use brake fluidfrom a sealed container. Contaminationwith dirt, water, petroleum products orother materials may result in brakesystem damage or failure. Failure toadhere to this warning could result in theloss of vehicle control, serious personalinjury or death.
WARNING: Do not allow the fluidto touch your skin or eyes. If thishappens, rinse the affected areasimmediately with plenty of water andcontact your physician.
WARNING: The brake systemcould be affected if the brake fluid levelis below the MIN mark or above the MAXmark on the brake fluid reservoir.
1.Park your vehicle on a level surface.
2.Look at the brake fluid reservoir to seewhere the brake fluid level is relativeto the MIN and the MAX marks on thereservoir.
Note:If the brake fluid level is between theMIN and the MAX marks on the reservoir, itis acceptable.
Note:If the brake fluid level is below theMIN mark or above the MAX mark, haveyour vehicle checked as soon as possible.
Note:To avoid fluid contamination, thereservoir cap must remain in place and fullytight, unless you are adding fluid.
Only use fluid that meets ourspecifications. See Capacities andSpecifications (page 291).
Brake Fluid Service Interval
Brake fluid absorbs water over time whichdegrades the effectiveness of the brakefluid. Change the brake fluid at thespecified intervals to prevent degradedbraking performance.
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as a stroke indicator to aid inadjustment checks. If the push rod isclean and the brakes are out ofadjustment, you can see the orangemarker protruding from the chamberwhen the brakes are applied.
•Checking the brake lining (every serviceinterval). When brake linings or blockswear within 0.063 in (1.6 mm) theymust be replaced.
•Periodic checking (every serviceinterval) of the air compressor filter.Check the filter minder and when theindicator is near or on the red linemarked Service, replace the filter andreset the service filter minder.
Do not back off or disconnect the frontbrakes so that they are less effective,letting the rear brakes do all the stoppingof your vehicle. Do not overlook the brakeson the trailer either. Brake condition on thetrailer is just as important as the tractor.Proper brake balance on trucks andtractor-trailers is essential for effectivebraking.
Once a year, inspect the entire brakesystem:
•Rubber components for deterioration.A qualified technician should inspectthese components and replace themas necessary. Replacement intervalsvary according to the severity andlength of vehicle service.
•Condition of brake drums, brakechambers and slack adjusters.
•System for air leaks.
•Hose or pipes for rust, damage anddeterioration.
•Operation of service and parkingbrakes.
Periodically inspect parts such as air brakechamber diaphragm, air compressor andair cleaner. Replace any parts if you canconsider them unserviceable.
Air Dryer
Climactic conditions affect performanceof desiccant or after-cooler type air dryers.You must establish a maintenanceschedule for each specific operation.
The use of an air dryer on a vehicle doesnot eliminate the need to drain the airreservoirs periodically.
Inspect for moisture in the air system byopening reservoirs, draincocks or valvesand checking for presence of water. Thepresence of small amounts of water dueto condensation is normal and is not anindication that the dryer is not functioningproperly.
Replace or rebuild the desiccant cartridgewhen you determine that the desiccant iscontaminated and does not have adequatewater absorption capacity. The desiccantchange interval may vary. A generalrecommendation is to replace thedesiccant every 12 months (yearly). Ifexperience has shown that extended orshortened life has resulted for a particularinstallation, then the yearly interval can beincreased or decreased accordingly.
Draining the Air Brake Reservoir
WARNING: Failure to drain airbrake reservoirs can result in a reductionor loss of braking ability due to fluidaccumulation in the reservoir and/orpossible freeze-up during cold weather.
Completely drain all the air brake reservoirsdaily by opening the draincock at the endsof the tanks. (Where accessible.Pull-chains are used when the drains areundercab or otherwise inaccessible.) Closethe draincock after draining. Manually drain
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any air tanks equipped with automaticmoisture ejector valves, as required, tomaintain a dry air system. Contact anauthorized dealer if you are unsure of theair reservoir locations or the drainingprocedure.
Hydraulic Brakes
Establish a regular schedule for periodiccleaning, lubrication and adjustmentinspection based on vehicle use. Exactmaintenance intervals are difficult topredetermine due to vehicle applicationsand operating conditions. If you areuncertain of the proper schedule for yourvehicle, contact an authorized dealer.
Regular inspections should include:
•Checking the brake lining (every serviceinterval). Establish inspection intervalsthat provide for lining replacementbefore damage to the disc occurs.Excessive lining wear may expose thebacking plate to the disc causingscoring of the disc faces. A qualifiedtechnician should perform this
inspection and keep to instructionsprovided by the service manual.Hydraulic brake systems arepower-assisted. There is a greatreduction in braking capabilitieswithout engine assist.
•Proper fluid level. The level should beat the bottom edge of the ring on eachreservoir fill port. Do not fill the mastercylinder to the top of the reservoir. Iffluid level requires attention tomaintain a proper master cylinder level,this is an indication of either severeoperation (pad wear) or fluid leakage.A more frequent and thorough brakeinspection is required.
•Brake lines, hoses and fittings. Repairor replace brake line tubes, hoses orfittings as required. Inspect thesecomponents every 4,000 mi(6,000 km) for the following.
•Lines for kinks, dents, corrosion orrupture.
•Hoses for abrasions, kinks, softspots or rupture, collapse, cracks,twists or loose frame supports.When replacing a hose, be surethere is adequate clearance to thehose to avoid an abrasion to thenew hose.
•All connections for leaks.
Driveline Parking Brake
WARNING: Use wheel chocks andexercise caution when inspecting underthe vehicle. A vehicle roll-away couldresult in property damage, personal injuryor death.
A qualified technician should adjust theparking brake and keep to the instructionsin the service manual.
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2.Set the parking brake and shift intoposition neutral (N) or park (P). Turnthe engine off.
3.Clean any dirt from around the axlefiller plug.
4.Remove the filler plug and inspect thelubricant level. It should be at thebottom of the filler plug opening.
5.Add lubricant, if necessary, through thefiller plug opening.
6.Clean and install the filler plug securely.
Changing the Fluid
Note:Drain the rear axle while the lubricantis warm.
1.Park your vehicle on level ground.
2.Set the parking brake and shift intoposition neutral (N) or park (P). Turnthe engine off.
3.Clean any dirt from around the axlefiller and drain plugs.
4.Remove the filler and drain plugs. Drainthe lubricant into a suitable container.Dispose of all used automotive fluidsin a responsible manner following yourlocal authorized standards.
5.Clean and install the drain plugsecurely.
6.Add lubricant through the filler plugopening.
7.Clean and install the filler plug securely.
SPRING U-BOLT CHECK
Check and tighten the U-bolt nuts afteryour vehicle has been operated under loadfor 1,000 mi (1,600 km) or six months,whichever occurs first.
Check and tighten the U-bolt nuts every37,000 mi (60,000 km).
Check and tighten the U-bolt nuts withyour vehicle at curb height and unloaded.
Inspect the U-bolt threads for rust anddebris. Clean the threads if contaminated.
U-bolt Nut Torque
Front Axle
Note:Check and tighten the U-bolt nutsevenly using a criss-cross pattern in thefollowing stages.
lb.ft (Nm)Stage
40 (60)1.
90 (125)2.
170 (225)3.
240 (325)4.
Rear Axle
Note:Check and tighten the U-bolt nutsevenly using a criss-cross pattern in thefollowing stages.
lb.ft (Nm)Stage
60 (75)1.
90 (125)2.
170 (225)3.
240 (325)4.
320 (440)5.
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Cooling system
•Protect against freezing temperatures.
•When removing your vehicle fromstorage, check coolant fluid level.Confirm that there are no coolingsystem leaks and that fluid is at therecommended level.
Disconnecting Your 12 Volt Battery
•Check and recharge as necessary. Keepconnections clean.
•If storing your vehicle for more than 30days without recharging the battery,we recommend that you disconnectthe battery cables to maintain batterycharge for quick starting.
Note:It is necessary to reset memoryfeatures if you disconnect the batterycables.
Brakes
•Make sure the brakes and parking brakerelease fully.
Tires
•Maintain recommended air pressure.
Miscellaneous
•Make sure all linkages, cables, leversand pins under your vehicle are coveredwith grease to prevent rust.
•Move vehicles at least 25 ft (7.5 m)every 15 days to lubricate working partsand prevent corrosion.
Removing Vehicle From Storage
When your vehicle is ready to come out ofstorage, do the following:
•Wash your vehicle to remove any dirtor grease film build-up on windowsurfaces.
•Check windshield wipers for anydeterioration.
•Check under the hood for any foreignmaterial that may have collectedduring storage such as mice or squirrelnests.
•Check the exhaust for any foreignmaterial that may have collectedduring storage.
•Check tire pressures and set tireinflation per the Tire Label.
•Check brake pedal operation. Driveyour vehicle 15 ft (4.5 m) back andforth to remove rust build-up.
•Check fluid levels (including coolant,oil and gas) to make sure there are noleaks, and fluids are at recommendedlevels.
•If you remove the battery, clean thebattery cable ends and check fordamage.
Contact an authorized dealer if you haveany concerns or issues.
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Materials
SpecificationName
WSS-M2C949-A, MERCON® ULVMotorcraft® MERCON® ULV Automatic Transmis-sion Fluid(U.S.)Motorcraft® MERCON® ULV Automatic Transmis-sion Fluid / MERCON® ULV huile pour boîtes auto-matique Motorcraft®(Canada)XT-12-QULV(U.S. & Canada)
BRAKE FLUID SPECIFICATION
Use fluid that meets the definedspecification and viscosity grade.
If you do not use fluid that meets thedefined specification and viscosity grade,it could result in:
•Component damage that your vehiclewarranty does not cover.
•Reduced brake performance.
Note:Keep brake fluid clean and dry.Contamination with dirt, water, petroleumproducts or other materials could result inbrake system damage and failure.
Capacities
QuantityVariant
Fill as required.All.
Materials
SpecificationName
WSS-M6C65-A3Motorcraft® DOT 5.1 Motor Vehicle Brake Fluid(U.S.)Motorcraft® DOT 5.1 Motor Vehicle Brake Fluid /Liquide de frein automobile DOT 5.1 Motor-craft®(Canada)PM-21(U.S. & Canada)
REAR AXLE FLUID CAPACITY
AND SPECIFICATION - DIESEL
Use fluid that meets the definedspecification and viscosity grade.
If you do not use fluid that meets thedefined specification and viscosity grade,it could result in:
•Component damage that your vehiclewarranty does not cover.
•Reduced vehicle performance.
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