Without a doubt, the Ford F-150 truck is one of the most popular trucks on the highway. The 2021 model comes with at least six powertrains, three cab configurations, and long and short bed lengths.

It is the perfect truck for heavy-duty work on and off-road with a maximum towing capacity of up to 14,000 pounds. The various models of the F-150 are Ford's performance flagship: rumor has it that an electric F-150 is on the way.

What is the Issue with F-150s?

A review of the older models, dating as far back as 2011 with a high volume of the 2015 and 2016 models, shows most owners complain of a vibration problem. Most drivers say it usually occurs at low speeds and begins to be very pronounced at around 40 mph.

Most dealers replace the tires, mounts, and other parts calling the vibration a normal condition since it is ubiquitous to F-150 trucks. But just because these trucks are vibrating does not mean this is regular or tolerable.

Drivers say the vibration feels like driving over wires laid across the road or even like driving on the safety warning ridges at the edge of the road.

Most note that with some more acceleration, the vibration smooths out but could return should they decelerate or get to higher RPMs. After several visits to dealers and mechanics alike, many F-150 drivers would like to understand what causes the vibrations and how to fix them permanently. Keep reading below to understand this issue.

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What is this vibration, what causes it, and how can it be spotted?

Research shows that most drivers of older models of the F-150 (especially 2015 & 2016 models) experience drivetrain vibrations at low speeds. A drivetrain is a group of components that provide power to the wheels so the truck can move.

It consists of the transmission, driveshaft, axles, and wheels. Drivetrain vibration is a condition where the whole vehicle body vibrates under acceleration.

Some of the most common causes are out-of-balance drivetrain components, such as a bent driveshaft or a worn universal or CV joint, worn slip splines, or out-of-phase yokes. At other times, a bad engine mount or transmission mount can cause vibrations.

Vibration problems in the F-150 must be diagnosed accurately and corrected quickly to avoid further damage to the drivetrain components. Let's look at the various types of drivetrain vibrations and how to spot them.

First, second and third-order drivetrain vibrations

A first-order drivetrain vibration will cause one shake or disturbance for each revolution of the driveshaft. In most cases, drivers feel these vibrations at speeds over 30mph. Out-of-balance components will only cause the first-order vibration, never any higher-order vibrations. First-order drivetrain vibrations are usually caused by:

• A component rotating at the same speed as the driveshaft that is out-of-round.
• A component rotating at the same speed as the out-of-balance driveshaft.
• Drive axle problems.

A second-order drivetrainvibration will cause two shakes or disturbances for each revolution of the driveshaft. Drivers usually feel second-order vibrations at very low speeds and higher speeds. Out-of-balance components will never cause a second or higher-order vibration, only a first-order vibration. Second-order drivetrain vibrations are usually caused by:

• Incorrect vehicle trim height.
• Powertrain mounting problems.
• Failed or failing U-Joints.
• Improperly phased or twisted driveshafts.
• Improper driveshaft angles.
• Drive axle problems.

Third-order drivetrain vibrations will cause three shakes or disturbances for each revolution of the driveshaft. This type of vibration is rare and not found in vehicles with Cardan U-joints.

This type of drivetrain vibration is diagnosed by removing the driveshaft and rotating the CV-joint through its full range of motion while feeling for any rough spots or looseness. Third-order drivetrain vibrations are usually caused by failed, failing, or binding Constant Velocity (CV) Joints.

How Do You Track Down a Drivetrain Vibration in Your Truck?

Drivetrain vibrations are tough to locate, so tool manufacturers have designed an ingenious device called a Chassis Ear.

It includes a set of microphones, wiring, and a headset. The chassis ear helps to track down any rogue vibrations and sounds you may notice in your vehicle. To use this device, follow the steps below:

1. Fix the microphones, via small spring clips, to the area you suspect the vibration originates.
2. String the wiring close to the outside and also inside of the vehicle body.
3. Connect the wiring to the headset.
4. Finally, wear the headset and monitor the sound while driving the vehicle.

So, how do you fix the vibrations in older models of the Ford F-150 at low speeds?

The most recommended simple fix is to change the driveshaft angle by weighing the bed down with at least 400 pounds of sandbags. But what is the point of driving a lightweight aluminum truck only to weigh it back with sand?

Another suggestion is to balance the tires. After much off-roading, the balancing in your F-150 will need to be corrected. Most F-150 models indicate a maximum load capacity of about 2,140 pounds, which means the tire pressure would be 35 PSI for a smooth ride.

If you use stock tires, check that your tire pressure matches the manufacturer's indication for the load your truck carries. Adjust accordingly, and you will notice a reduction or total elimination of vibrations.

But the above has not proven to give most F-150 drivers a reliable fix to the vibrations. It may subside for a while but could start vibrating after a couple of miles of acceleration.

What Actually Works?

One fix, applied to the 2015 2-Wheel Drive Lariat SuperCab model, was proven to eliminate vibrations. You could research drivelines to get a better understanding of the components specific to your particular F-150 model. You can then apply this knowledge when attempting to fix the vibration problem. Please see the steps below:

1. Add a 2.5 level to the truck front. 2-Wheel Drive models do not have a block at the back. The addition helps to level the truck properly. This changes the angle of the front driveshaft so that the working angles of the U-joints at the rear and the carrier bearing end of the long second driveshaft are now more out but not canceling the vibration.
2. Look under the truck to take note of the clips with nuts that clip on the frame mount. The carrier bearing mount tightens to the bottom of those clips, about 2 millimeters from the frame mount.
3. Cut the clips but leave the rounded position that stops the nut from turning until it is snug. This allows the carrier bearing to move up the aforementioned 2 millimeters and bolts tight to the frame mount with no clip in between.
4. Move the carrier bearing mount about 2 millimeters up. This gets the working angles of the two rear U-joints about half a degree closer. Thus, canceling out the vibration.
5. In this step, you have to play by eye: center bolt the carrier bearing bracket, so the drivelines line up as close as possible. This should not be too difficult as the bearing has a bushing.
6. As an added measure, ensure your truck tires' pressure is at optimal levels. You could also replace your rear shocks, as they tend to wear out faster in trucks like the F-150.

And presto!!! You are good to go! These steps could also remedy vibration problems in 4-Wheel Drive models.

Conclusion

Given its popularity among truck enthusiasts, the Ford F-150 is not going anywhere soon. It is revered as the Best Truck to buy due to its price and performance delivery. Plus, it has an incredibly high reliability rating, providing confidence in drivers when they purchase this award-winning truck.

With current models, Ford has been able to take out the vibration issues of earlier models. However, this article is a perfect guide on how to fix the vibrations at low speeds.

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