2020-2025 Lincoln Aviator Front Knee & Bearing: Noises, Recalls, and Replacement Costs

Symptoms of a Failing Front Knee Assembly

Failures in the front knee assembly typically originate from the moving parts it contains: the wheel bearing and the lower ball joint. The knuckle itself is a solid piece of metal that rarely fails unless it's cracked in a collision or has a manufacturing defect (see recall section below).

Noises

• Humming, Roaring, or Grinding: This is the classic sign of a bad wheel bearing. The noise is rotational, meaning it starts as soon as the vehicle is moving and increases in pitch and volume with speed. It's often described as a low hum or growl that can be heard and felt inside the cabin. To help pinpoint the source, the noise may change or get louder when turning left or right, as this shifts the vehicle's weight onto the failing bearing.
• Clunking or Popping: A sharp clunking or popping sound, especially when driving over bumps, speed bumps, or making low-speed turns, usually points to a worn-out ball joint. The ball joint connects the knuckle to a control arm, and excessive play in the joint will cause it to knock against its housing.
• Squeaking and Creaking: Some Aviator owners have reported creaking or squeaking noises from the front end when turning or going over bumps. While this can be caused by a dry or failing ball joint, it can also be related to other suspension components like struts or sway bar links.

Vibrations and Steering Feel

• Steering Wheel Vibration: A worn wheel bearing can cause vibrations that are felt in the steering wheel, especially at highway speeds.
• Loose Steering or Wandering: If the steering feels less precise or the vehicle tends to pull to one side, it can be a symptom of a severely worn ball joint or wheel bearing. This indicates excessive play in the assembly, which affects wheel alignment and control.
• ABS Light: The wheel speed sensor, which is part of the Anti-lock Braking System (ABS), is located at the wheel hub. A failing wheel bearing can create excessive movement (wobble) that damages the sensor or disrupts its reading, potentially causing the ABS warning light to illuminate.

Known Issues, Recalls, and Technical Service Bulletins (TSBs)

The 2020-2025 Lincoln Aviator has a significant safety recall directly related to the front steering knuckle.

While other recalls exist for the Aviator concerning rear suspension bolts and subframe bolts, 20S69 is the most critical one for the front knee assembly. No specific Technical Service Bulletins (TSBs) for the front knee assembly were identified at the time of this writing.

Buying a Used 2020-2025 Aviator Front Knee Assembly: What to Look For

A used OEM knee assembly can be a cost-effective solution, but careful inspection is key. The main value is in the knuckle casting itself; the included wheel bearing and ball joint should be considered wearable items with a limited lifespan.

AWD vs. RWD: The Most Critical Check

The single most important factor is ensuring compatibility between All-Wheel Drive (AWD) and Rear-Wheel Drive (RWD) models. An AWD knuckle must accommodate a CV axle shaft, while an RWD version does not. While many OEM parts suppliers list the same part numbers for both AWD and RWD knuckles, the workshop manuals specify different replacement procedures. This suggests the hub and bearing assembly pressed into the knuckle is different. Do not assume they are interchangeable.

Physical Inspection Steps

1. Check the Wheel Bearing: With the assembly off the car, try to spin the wheel hub by hand. It should rotate smoothly and silently. Any grinding, roughness, or noise indicates the bearing is bad. Grab the hub and try to wiggle it; there should be zero play or wobble.
2. Inspect the Ball Joint: The knuckle assembly includes a new lower ball joint. Check that the rubber boot is not torn or leaking grease. A torn boot allows dirt and water to enter, causing rapid wear.
3. Look for Collision Damage: Carefully inspect the entire knuckle for cracks, bends, or deep gouges. Pay close attention to the mounting points for the control arms, strut, and brake caliper. A part from a vehicle involved in a front-end collision may have hidden damage that compromises its structural integrity and your safety.
4. Consider Mileage: The wheel bearing is a wear item. A general lifespan is 75,000 to 150,000 miles. An assembly from a low-mileage vehicle (under 50,000 miles) is ideal, as the bearing likely has significant life left. If purchasing a high-mileage assembly, budget for the cost of pressing in a new wheel bearing.

Replacement Overview & Special Procedures

Replacing the steering knuckle is an advanced repair that requires specialized tools and a high degree of mechanical skill. It is not recommended for beginners.

Key Steps & Considerations

• The process involves removing the wheel, brake caliper and rotor, ABS sensor, and axle nut (on AWD models).
• The upper control arm, lower control arm, and outer tie rod end must be disconnected from the knuckle. This requires a ball joint separator tool. The factory service manual specifically warns against using a hammer or pickle fork, as this can damage the ball joint boots or the knuckle itself.
• One-Time-Use Hardware: Many suspension bolts, and especially the large axle nut on AWD models, are torque-to-yield. This means they are designed to be tightened once and must be replaced with new ones during reassembly to ensure safety.
• Torque Specifications: Correct torque on all fasteners is critical for safety. While specific values were not available in public sources, you must obtain the correct torque specs from a factory service manual for the axle nut, ball joint nuts, tie rod nut, and brake caliper bolts.
• Post-Installation Alignment: A full four-wheel alignment is mandatory after replacing a steering knuckle. Skipping this step will result in poor handling, unsafe driving characteristics, and rapid, uneven tire wear.

Cost Comparison: New vs. Used Aviator Knee Assembly

Prices can vary based on location and supplier. The costs below are estimates to help understand the value of different options.

Frequently Asked Questions (FAQ)

Part Number Reference

Note: While most suppliers list these part numbers for both AWD and RWD models, it is essential to confirm fitment with your vehicle's VIN before ordering due to potential differences in the required hub and bearing assembly.