Does 2004 navigator have lifetime sealed joints

Most cars have non greasable ball joints. When they go bad they are replaced with greasable ones. Unusual wear on tires or looseness in steering or a clunking sound coming for the front are all signs of need for replacement of, at least some , front end part(s).

To perform the following procedure, the lower control arm must be removed from the vehicle. Refer to Removal And Installation for that procedure.

1. Using a screw driver or other suitable tool, pry the seal boot off of the ball joint assembly
2. Position receiving cup, Special Tool 6758 to support lower control arm when removing ball joint assembly. Install Remover, Special Tool 6919 on the top of the ball joint assembly.
3. Using the arbor press, press the ball joint assembly completely out of the lower control arm.

NOTE: When installing ball joint in lower control arm, position the ball joint in control arm so notch in ball joint stud is in the direction shown. This will ease assembly of the ball joint to the steering when installing pinch bolt.

1. By hand, position ball joint into ball joint bore of lower control arm. Be sure ball joint is not cocked in the bore of the control arm, this will cause the ball joint to bind when being pressed into control arm.

 

1. Position control arm with installed ball joint, in an arbor press with Receiving Cup, Special Tool 6758 supporting the lower control arm. Then center Installer, Special Tool 6908-4 on the bottom of the ball joint
2. Carefully align all pieces. Then press the ball joint into the lower control arm until it is completely seated against surface of lower control arm. The ball joint is correctly installed when there is no gap between the ball joint and the lower control arm. Do not apply excessive force against the ball joint or the lower control arm.
3. Install a NEW seal boot by hand as far as possible on the ball joint. Installation of the seal boot is to be with the shield positioned as shown.

CAUTION: Do not use an arbor press to install the sealing boot on the ball joint. Damage to the sealing boot will occur if excessive pressure is applied to the sealing boot when it is being installed.

1. Place Installer, Special Tool 6758 over seal boot and squarely align it with bottom edge of seal boot. Apply hand pressure to Special Tool 6758 until seal boot is pressed squarely against top surface of lower control arm.

CAUTION: A replacement ball joint is not pre-lubricated. Properly lubricate the replacement ball joint using Mopar Multi-Mile grease or an equivalent. Lubricate ball joint after seal boot is installed but prior to top of seal boot being pushed down below notch in ball joint stud. Air must vent out of the seal boot at notch when grease is pumped into ball joint, failure to do so will balloon and damage seal boot. Do not over grease the ball joint, this will prevent the seal boot from pushing down on the stud of the ball joint.

CAUTION: After the ball joint is properly greased, clip the end of the grease fleeing off below the hex. The ball joint seal boot is non-purgeable and further greasing is not required and can result in damage to the seal boot.

1. Reinstall lower control arm on vehicle.

That is a very strong possibility, however I think that your husband would have made certan that the seal was seated propperly. So all you can do is change the seal again. Make sure you inspect the cv shaft where the seal rides for any vissable damage sharp cut marks, dents or scrapes. Also lubricate the in side of the seal with some grease upon installation. Take care when slidding the cv shaft into place so no damage can occure to the seal. Good Luck, From Ernie @ RedDeer, Alberta, Canada.

60,000 Mile Service Schedule

• Inspect 4x2 front wheel bearings; replace grease and grease seals, and adjust bearings
• Change automatic transmission fluid
• Inspect automatic transmission fluid level (if equipped with underhood dipstick)
• Replace fuel filter
• Perform multi-point inspection
• Inspect and lubricate all non-sealed steering linkage,ball joints,suspension joints,half and drive-shafts and u-joints
• Inspect brake pads/shoes/rotors/drums, brake lines and hoses, and parking brake system
• Inspect complete exhaust system and heat shields
• Inspect engine cooling system and hoses
• Replace engine air filter
• Change engine oil and replace oil filter (Up to 5 quarts of oil. Perform at specified mileage interval or every 6 months, whichever occurs first)
• Rotate and inspect tires; check wheel end play and turning noise

There are places to lubricate the joints and such in the front end. The ball joints certainly have lube points if nothing else does. Anything that could be metal to metal contact needs periodic lubrication. Check your owners manual for Lubrication types. Most are using a molediumdysulfide based lubricant in the newer vehicles. It is easily available at Walmart and most auto parts stores. Just don't use a graphite based Lube unless it is specifically called for. If your owners manual is short on information on this you should pick up a Haynes repair manual on your vehicle. It will specify lube points and intervals and what type of lubrication to use.

I would double check all u joints for rust, play, and proper lubrication. If it is squeeking, than it is likely it is u-joints. Let me know if you need anything else.

Prevent road dirt and water getting into the seals and bearings

There is normally a universal joint in there which needs to be lubricated

Once the gaiter has split the lubricant is diluted by water, grit gets into the joint and they wear out quicker

"Simples" as the Meerkat would put it

Most are sealed. You just need to look. Sometimes if aftermarket parts are intalled (ball joints, universal joints) they will have grease fittings where the OEM did not.

I think you mean 'ball-joints,' part of the steering and suspension.
Most modern vehicles, with some exceptions, no longer have the Zerk fittings once found on each ball-joint, but 'lifetime' lubrication packed into the joint and decently sealed to prevent loss of grease and incursion of dirt and moisture. You may have sealed ball or roller bearings used in your wheels since the cone-type, adjustable bearings are also less common than they once were.
In my experience, these sealed assemblies have become ever more reliable as materials and manufacturing techniques have steadily improved.  Many such assemblies now really do last the usable life of our vehicles.    

Normal Maintenance Details
90,000 Miles (144,000 Kilometers) : All Applicable Models
PERFORMED OPERATION COMPONENT
INSPECT BALL JOINTS
If equipped.
INSPECT BRAKE SYSTEM
Inspect brake pads, shoes, rotors, drums, brake lines & hoses.
INSPECT COOLING SYSTEM HOSES & CLAMPS
INSPECT DISC BRAKE PADS & ROTORS
INSPECT DRIVESHAFT
If equipped.
INSPECT DRIVESHAFT/PROPELLER SHAFT U JOINTS
INSPECT EXHAUST SYSTEM AND HEAT SHIELDS
INSPECT PARKING BRAKE SYSTEM
INSPECT STEERING LINKAGE
INSPECT SUSPENSION COMPONENTS
LUBRICATE DRIVESHAFT/PROPELLER SHAFT U JOINTS
LUBRICATE STEERING LINKAGE
REPLACE AIR CLEANER/ELEMENT
REPLACE AUTOMATIC TRANSMISSION FLUID
REPLACE CABIN AIR FILTER
If equipped.
REPLACE CLIMATE-CONTROLLED SEAT FILTERS
If equipped.
REPLACE ENGINE OIL
REPLACE ENGINE OIL FILTER
REPLACE FUEL FILTER
ROTATE TIRES
90,000 Miles (144,000 Kilometers) : RWD
PERFORMED OPERATION COMPONENT
LUBRICATE BALL JOINTS
2000 Lincoln Navigator
Maintenance
...sorry if not too readable