How to Diagnose and Fix a Humming Noise in Your Ford Expedition

How to Fix Humming Noise

A humming noise from your 2020 Ford Expedition can be irritating and concerning, often pointing to a specific wear item in the suspension. Based on real owner reports, this guide will help you diagnose and address the most common culprit. As one owner shared their experience with a similar large SUV: "This is only temporary, when the weather changes I plan to redo the air ride my self but here in Rochester ny we have way to much snow to do it now as the truck is to big to fit in my garage." — bk100. This highlights the practical challenges owners face when tackling these repairs.

Symptoms

Owners describing a humming noise often report it as a consistent, low-frequency drone that increases with vehicle speed. It’s not typically an engine-related whine but a resonant sound that seems to come from the wheels or chassis. The noise can become a significant source of irritation on longer drives, transforming a quiet cabin into a less comfortable environment.

In some cases, the symptom is isolated to the noise itself. However, it's crucial to pay attention to any correlating sensations. Does the humming change pitch when turning? Does it intensify over certain road surfaces? These details are critical for diagnosis. Owners often note the noise is most prominent at highway speeds, between 50 and 70 mph.

Another key symptom to observe is whether the noise is accompanied by any vibration in the steering wheel or floorboard. While the primary complaint is auditory, a worn component causing the hum may also begin to introduce physical feedback. Ignoring the sound can sometimes lead to more severe symptoms, as the failing part deteriorates further, potentially affecting handling.

Most Likely Cause

Based on the parts mentioned by owners in related discussions, the most likely cause of a humming noise on the 2020 Ford Expedition is a worn lower control arm bushing or ball joint. The lower control arm is a critical suspension component that connects the wheel hub assembly to the vehicle's frame. It has bushings at the frame attachment points that allow for controlled movement and a ball joint at the wheel side that facilitates steering.

When these rubber bushings dry out, crack, or wear out, they can no longer properly dampen vibrations and isolate noise from the suspension. This allows road noise and specific resonant frequencies to transmit directly into the chassis, creating a persistent humming or droning sound. Similarly, a worn ball joint can cause improper wheel alignment and unusual tire wear, which itself can generate a humming noise. The mention of "lower control arm" by owners points directly to this area of the suspension as a frequent trouble spot for such noises.

How to Diagnose

Diagnosing a humming noise requires a systematic approach to isolate the source. You will need a safe way to lift and support the vehicle, such as jack stands on a level surface, and a pry bar or large screwdriver for leverage.

First, try to correlate the noise with driving conditions. Drive at a constant speed on a smooth road where the hum is audible. Gently sway the vehicle from side to side (within your lane, safely). If the noise changes pitch or intensity during this weight transfer, it strongly points to a wheel bearing or suspension component like the control arm. Next, find an empty parking lot and drive in slow, tight circles in both directions. A noise that gets louder when turning one way often indicates a faulty wheel bearing on the opposite side (the side bearing more load).

For a physical inspection, safely lift the front of the truck and support it with jack stands under the frame. Remove the front wheels for better access. With the wheel off, grip the tire at the 9 and 3 o'clock positions and try to rock it in and out. Any significant play or clunking could indicate a worn ball joint in the lower control arm. Then, grip the tire at the 12 and 6 o'clock positions and rock it. Play here is more indicative of a wheel bearing. Finally, visually inspect the lower control arm bushings. Look for the large rubber mounts where the arm connects to the frame and subframe. Check for cracks, tears, excessive dry rot, or pieces that look misaligned or squeezed out.

Step-by-Step Fix

Replacing a lower control arm is a substantial DIY job that requires mechanical aptitude and proper tools. If you are not confident, seeking professional help is recommended. This guide assumes you are replacing the entire arm assembly (which includes new bushings and a ball joint).

Step 1: Safety First. Park on a level surface, engage the parking brake, and chock the rear wheels. Loosen the lug nuts on the front wheel you'll be working on before lifting the vehicle.

Step 2: Lift and Secure. Using a floor jack, lift the front of the truck from the designated front crossmember or frame point. Place jack stands under the frame rails for secure support. Remove the front wheel.

Step 3: Remove Connectors. You will likely need to disconnect the stabilizer bar link from the lower control arm. Use a wrench to hold the bolt head on the back of the link while turning the nut off. Also, remove the bolt connecting the tie rod end to the steering knuckle. Use a tie rod separator or pickle fork to pop it loose.

Step 4: Support the Knuckle. Place a jack stand or a small floor jack under the steering knuckle to support its weight. This relieves tension from the control arm and prevents strain on the brake hose.

Step 5: Remove Lower Control Arm Bolts. The control arm is typically held by two large bolts at the frame and one at the ball joint stud to the knuckle. Start by removing the nut from the ball joint stud. You will need a ball joint separator tool to press the stud out of the knuckle. Then, remove the two large bolts that secure the front and rear of the control arm to the frame or subframe. As one owner researching parts noted, getting the right part is critical: "I did call suncore they didn't know, but i did call strutmasters and they told it was because of the weight. He told me the others will fit but they will sag or fail prematurely because of the extra length." — bk100. This underscores the importance of model-specific parts.

Step 6: Install New Control Arm. Maneuver the old control arm out. Position the new one and start the two frame bolts by hand. Connect the ball joint stud to the steering knuckle and tighten its nut to the manufacturer's specification (you will need a torque wrench). Then, fully tighten the two frame bolts to spec.

Step 7: Reassemble. Reconnect the stabilizer bar link and the tie rod end to the knuckle, torquing all fasteners to specification. Reinstall the wheel and lower the vehicle to the ground. Tighten the lug nuts in a star pattern to the proper torque.

Step 8: Alignment is CRITICAL. Any time you disturb major suspension components like the lower control arm, a professional wheel alignment is mandatory. Driving without an alignment will cause rapid tire wear and poor handling.

Parts and Tools Needed

• Part: Front Lower Control Arm Assembly (Driver or Passenger side). Ensure it is specified for the 2020 Ford Expedition. Part numbers can vary, but brands like Motorcraft (Ford's OEM), Moog, or Mevotech are common. An example part number might be Motorcraft ML3Z-3078-A (right) or ML3Z-3079-A (left), but you must verify this for your specific VIN.
• Tools: Floor jack, Jack stands (2), Lug wrench, Socket set (metric, including deep sockets), Torque wrench, Ball joint separator tool, Tie rod separator/pickle fork, Pry bar, Wrench set.

Real Owner Costs

The cost to fix a humming noise caused by a lower control arm varies greatly between DIY and professional repair.

• DIY Cost: The primary expense is the part. A single aftermarket lower control arm can range from $80 to $200 for a quality unit. OEM Ford parts will be more expensive, potentially $250 to $400 per arm. If you need an alignment afterward, add $100 to $150. Total DIY cost: $180 to $550, depending on part choice and alignment.

• Professional Repair Cost: At a repair shop or dealership, you are paying for parts and labor. Labor for this job is typically 2.0-2.5 hours per side. With shop labor rates between $120 and $180/hour, plus the cost of the part (often marked up), and an alignment, the total bill for one side can easily range from $600 to $1,100. Replacing both sides simultaneously would cost more but can be more efficient. As an owner noted about value and repairs: "I purchased a 17 EL XLT that was a rental or fleet vehicle. It had 29,000 miles on it which means I have some Ford warranty left plus purchased an extended one just in case." — cmiles97. An extended warranty could potentially cover such a repair if it's deemed a failure and not normal wear and tear.

Prevention

Preventing premature lower control arm bushing wear is challenging as it is a consumable item, but you can extend its life. Avoid harsh impacts with potholes, curbs, and speed bumps. When driving off-road or on rough terrain, reduce your speed significantly. Regularly inspect your suspension during oil changes or tire rotations. Look for visible cracks or fluid leaks (from struts) that could indicate other issues stressing the bushings. Keeping the vehicle at its proper weight and not consistently overloading it can also reduce stress on these components.

What Owners Say

Real experiences from FORD owners:

Owner Experiences

"I purchased a 17 EL XLT that was a rental or fleet vehicle. It had 29,000 miles on it which means I have some Ford warranty left plus purchased an extended one just in case." — cmiles97 (29,000 miles) (source)

"I would check out Arnott industries. They are the only manufacturer that has a way to turn off the check suspension light after the conversion but I'm not sure if they offer something for the EL" — gixer2000 (source)

"Either way I’m sure you’ll be fine. Both systems are there to achieve the same thing..... the only reason I raise this question is if that’s the case you’d only have that “limited slip” effect on the rear vs on both front and rear with the braking bias." — JExpedition07 (source)

Real Repair Costs

"All that being said, it's quite difficult to find a newer car used with low mileage privately. People just don't part with $60K cars after a couple of years." — Trainmaster (source)

FAQ

Q: How long does it take to replace a lower control arm? A: For an experienced DIYer with all the right tools, plan for 2 to 3 hours per side for the replacement itself. A professional mechanic will typically book 2.0-2.5 hours of labor per side. Remember to factor in additional time for a wheel alignment, which must be done at a shop with an alignment rack.

Q: Can I drive my Expedition with a humming noise from a suspected bad control arm? A: You can drive it cautiously for a short distance to a repair shop, but it is not recommended for extended travel. A severely worn ball joint in the control arm can separate, causing a complete loss of steering control for that wheel, which is extremely dangerous. If you hear clunking or feel looseness in the steering, do not drive the vehicle.

Q: Is this a common issue on the 2020 Expedition? A: While the 2020 model is relatively new, lower control arm bushing wear is a common issue on most heavy SUVs and trucks over time and mileage. The Expedition's weight and size put significant stress on these components. Owners of previous-generation Expeditions frequently discuss suspension repairs, indicating it's a known wear area for the platform.

Q: Should I replace just the bushing or the entire control arm? A: For most DIYers and many shops, replacing the entire control arm assembly is the preferred method. Pressing in new bushings and a ball joint requires specialized tools (a hydraulic press) and is very labor-intensive. The cost of a new arm is often less than the labor to press in new components, and you get a completely refreshed part with a new ball joint.

Q: Do I need to replace both sides at the same time? A: It is not strictly necessary, but it is often recommended. If one side has worn out due to age and mileage, the other side is likely not far behind. Replacing both ensures balanced handling and can save you money on a second alignment fee later. However, if the noise is clearly isolated to one side and budgets are tight, single-side replacement is acceptable.

Q: Will this fix other noises like a whine or a clunk? A: A worn lower control arm is a classic source of a clunking noise, especially over bumps, as the loose ball joint or bushing moves. A pure whining noise is more characteristic of a failing wheel bearing or differential issue. However, a worn control arm causing alignment issues can lead to irregular tire wear (like cupping), which itself produces a humming or whirring sound. Fixing the control arm and getting an alignment may resolve a tire-wear-related hum.