Ford F150 Rear Differential Problems: Reasons & Easy Fixes!

Bad Ford F-150 rear differential may present some symptoms such as unusual noise, smoking, and fluid leakage. Other signs of a problematic rear differential include a disconnected driveshaft and failure of the electronic locking differential (ELD) to unlock. To prevent further damage, these issues need to be addressed immediately.

This is not everything that can help you to get rid of the Ford F150 rear differential problems. Therefore, keep reading for a comprehensive solution. 

5 Symptoms of Ford F150 Rear Differential Problems

The following tabular representation provides a concise summary of the symptomatic manifestations, their underlying etiologies, and the corresponding remedial measures.

Symptoms Reasons Solutions
Unusual noise from the rear endPinion bearing failure Replace the bearing
Debris and metal chunks in the rear endClean the pinion and bearing
Low fluid levelRefill the fluid
Rear differential smoking A faulty bearing, gearsReplace the faulty part
Fluid leakage from the rear endWorn gasketReplace the gasket
Driveshaft disconnected from the differentialDeterioration of the flange yokeReplace the flange yoke 
Electronic locking differential (ELD) not unlockingELD switch brokenReplace the ELD switch

As you’ve already got the quick overview, now let’s move on to the explanatory discussion. 

Symptom 1: Unusual Noise From The Rear End

One of the most common symptoms that indicate the Ford F150 rear differential has a problem is unusual noise from the rear. This unusual noise includes whining or humming noise, clunking, or banging noise. There can be a number of reasons for this problem.

In the next bit, I’ll discuss the reasons along with their remedy.

Reason 1: Pinion Bearing Failure

The pinion bearing is a vital component of the Ford F150’s rear differential. The failure of this component results in an unusual noise coming from the rear of the vehicle.

The pinion gear, which transfers power from the engine to the differential, is supported by the pinion bearing. Follow the list to diagnose the source of the problem.

  • Humming noise: Incorrectly installed ring gear and pinion gear, worn-out bearings
  • Noise when accelerating/decelerating: Heavy contact of the pinion-gear teeth on the outer ends of the ring-gear teeth (pinion gear not set deep enough), not enough tooth contact (too much backlash).
  • Knocking noise: Worn-out splines on the axle shafts, and chipped teeth on one or more gears in the differential.
  • Noise when turning: Bad axle bearing, tight-meshing pinion gears, too much backlash on pinion gears, worn-out differential-case bearings.

Solution: Replace the Pinion Bearing

Ford F-150 rear differential replacement requires the following tools and components.

  1. A socket wrench
  2. Wrench to remove the 12 mm bolt 
  3. New pinion bearing
  4. A bucket
  5. A flat-headed screwdriver
  6. New rear differential fluid
  7. A hydraulic lifting jack

Having acquired these tools, you can proceed to the next step.

Step 1: Lift the Rear End Of The Ford F-150

Utilize the hydraulic jack to elevate your Ford F-150 to a suitable height that provides sufficient clearance beneath the vehicle for carrying out the intended task. Video tutorials are available for visual guidance on the process.

Step 2: Open the Rear Differential

Before starting the rear differential’s opening procedure, it is recommended that you place a bucket underneath it. This will enable a seamless fluid drainage process into the container. 

Start by loosening the four bolts that secure the rear differential cover with a 12 mm wrench. The rear differential fluid should be drained easily into the bucket by partially loosening the bolts and inserting a screwdriver between the two covers. After the fluid has drained, remove the bolts completely and gently remove the cover.

Step 3: Inspect the Pinion Bearing and Carefully Remove the Faulty Bearing

The rear differential of the vehicle comprises numerous pinion bearings. Before repair can begin, the exact pinion bearing that is malfunctioning must be identified. It is possible to identify the faulty pinion bearing by visually inspecting it as there will be visible signs of wear. As soon as you identify the defective pinion bearing, you will be able to replace it.

Below is an image of a typical faulty pinion bearing which serves as a visual reference to help you understand what a faulty pinion bearing looks like.

The pinion bearing is secured in place by a set of lugs and bolts. To disengage the bearing, you need to unscrew all the bolts with a socket wrench. This will allow the bearing to be easily removed.

Step 4: Install the New Pinion Bearing 

Install the new pinion bearing at its designated location and tighten all the bolts with a socket wrench. Ensure that the bolts are tightened to their optimal torque level.

Step 5: Reinstall the Cover Back

Put the differential cover back in the palace and secure it with the bolts that you unscrewed. Tighten all the bolts evenly at a similar torque. 

Step 6: Refill the Rear Differential Fluid

Refill the fluid into the rear differential at an optimum level to ensure the proper rotation of the pinion bearing. If you need guidance on how to refill the fluid into the rear differential, refer to this video here. 2016 F150: Rear Differential Fluid Change

With this, you are done with the process of the Ford F150 rear differential replacement. But it’s not as simple as it sounds. It is always recommended to do so with the assistance of an automobile engineer.

Reason 2: Debris And Metal Chunks In The Rear End

When the debris and metal chunks get caught in the gears of the differential, it can create a grinding or clunking noise. Due to friction and damage to the differential, the gears are unable to rotate smoothly against each other, causing this noise.

To check for debris and metal chunks in the rear differential of a Ford F-150, follow these steps.

  1. Start by removing the fill plug.
  2. Check for any signs of damage or wear.
  3. Next, remove the cover of the differential.
  4. The cover is typically held in place with bolts that are almost always 1/2 inch.
  5. Use a piece of metal to carefully pry off the cover, making sure not to damage the mating surfaces.
  6. Once you have removed the cover, drain the fluid completely.
  7. Inspect for any metal shavings or debris.
  8. It’s normal to see some wear and tear, but if you notice anything serious, have a mechanic check it out.

Solution: Clean The Pinion And Bearing

Cleaning the Ford F-150 rear differential is almost identical to the replacement process. Anyway for a better visual guide on how to clean the Ford F-150 rear differential and refill the fluid into it watch the video below. 

Reason 3: Low Fluid Level

Insufficient fluid levels in the rare differential of the Ford F-150 can induce a typical noise. Such noise results from the inadequacy of lubrication for the gears inside the differential, leading to abrasive friction between them. As a result, the rear differential produces unusual sounds due to the friction.

You can check the fluid level in the rear differential simply with a dipstick. If the dipstick shows the fluid level is low or medium you may need to refill the fluid in the rear differential. 

Solution: Refill the Fluid

To refill the fluid into the Ford F-150 rear differential follow the video provided in the clean pinion bearing. For the Ford F-150 rear differential, Valvoline High-Performance Transmission & Differential Gear Oil: Conventional 80W-90, 1 Gallon (Part No. 773732) is recommended. Always, refer to the manufacturer’s guideline.

Symptom 2: Rear Smoking

Smoking from the rear differential is another major symptom of rear differential problems. Several reasons can trigger this issue. In the following segment, I’ll have a detailed discussion of those reasons and their potential solution. 

Reason: Faulty Bearings and Gears

A bad bearing can cause excessive friction with the other components, resulting in a great deal of heat. Consequently, you may see some smoke coming out from the rear differential. When this type of situation arises you should get it fixed as early as possible. 

Solution: Replace the Bearing and Gear

I’ve already mentioned a comprehensive step-by-step guide on how to replace the rear differential gear pinion gear and bearing in the section above. You can simply check the section to know how to replace the rear differential pinion bearing. 

However, you should keep in mind that this is quite a difficult process. If you feel you won’t be able to complete these processes properly, it’s advisable to contact an automobile mechanic.

Symptom 3: Fluid Leakage From The Rear End

Leaking fluid from the rear differential is a major symptom of Ford F-150 rear differential problems. It can even lead to further damage like emission, worn-out pinion bearing, or damaging the rear differential as a whole. 

Reason: Worn Gasket

The main reason behind the fluid leakage is the worn gasket. The gasket protects the fluid leakage from the two cover connecting points. If the gasket gets bad then it can cause fluid leakage. In case of a worn gasket, you need to replace it immediately.

Solution: Replace the Gasket

To replace the rear differential gasket follow these steps. But before going to the steps gather the following tools and components. 

  1. A wrench 
  2. A flathead screwdriver 
  3. A new gasket 
  4. A bucket

Once you’ve gathered these tools, move to the steps below. 

Step 1: Open the Rear Differential Cover and Drain the Fluid into a Bucket

To open the rear differential cover and drain out the rear differential fluid into the bucket follow step 1 and 2 of replacing the rear differential pinion bearing. 

Step 2: Remove the Old Worn Gasket 

After opening the rear differential cover, gently remove the rear differential cover. After that, wipe the place where the gasket is placed with a soft cotton cloth. Wipe it carefully and clear all the dirt and debris or metal chunks.

Step 3: Install New Gasket

Now place the new gasket in the place the old one was. Be careful about the placement, make sure the gasket is fitted in place perfectly. 

Step 4: Reinstall the Cover and Refill the Fluid

To reinstall the rear differential cover and refill the fluid follow steps 5 and 6 of replacing the pinion bearing of the rear differential. 

Symptom 4: Driveshaft Disconnected From The Differential

The driveshaft connects the transmission to the differential, which transfers power to the wheels. It is impossible for the vehicle to move if the driveshaft is disconnected from the differential. Several reasons can trigger this issue.

Reason: Deterioration of the Flange Yoke

The flange yoke provides a secure attachment point for the driveshaft, allowing it to transfer torque from the engine to the wheels. Over time, the flange yoke can deteriorate due to wear and tear, corrosion, or damage from impacts. 

If the flange yoke becomes worn or damaged, it may no longer provide a secure attachment point for the driveshaft. When this happens, the driveshaft can become disconnected from the rear differential and lose power to the wheels.

Moreover, when the flange yoke deteriorates, the driveshaft can vibrate or wobble, damaging other drivetrain components as well. 

Solution: Repair the Flange Yoke 

To replace and repair the flange yoke follow the guideline below. But before that here are the tools and components you’ll need for this job:


  1. Jack and Jack stands
  2. Soft rubber mallet
  3. File
  4. Carburetor spray
  5. Silicone grease
  6. Socket wrench and sockets


  1. New flange yoke

Step 1: Jack Up The Vehicle Safely And Remove The Driveshaft

Lift the vehicle and secure it using a jack and jack stands. Remove the driveshaft from the transfer case or the rear of the transmission. If the driveshaft is stuck, use a soft rubber mallet to break it loose. Gently and firmly pull it backward to remove it.

Step 2: File Down The Burrs On The Slip Yoke

File down the burrs on each tooth of the slip-yoke spline with a file. Do this for every tooth inside the spline.

Step 3: Clean The Spline Thoroughly

Use carburetor spray to clean the inside of the spline thoroughly, making sure no metal filings are left over.

Step 4: Grease The Slip Yoke

Apply silicone grease to the inside and outside of the slip yoke.

Step 5: Replace The Driveshaft

Insert the driveshaft into the transfer case or the rear of the transmission. Be careful not to damage any teeth on either side of the coupling. Bolt the back end of the driveshaft first by feeding them in by hand and then tightening them in an X pattern with a socket wrench and sockets. Make sure the bolts are nice and snug.

That’s it! You’re done with the whole process. However, you can also refer to the video below for visual guidance. Drive Shaft Removal and Slip Yoke Service Ford F-150 2011-2014

Symptom 5: Electronic Locking Differential (ELD) Not Unlocking

The Electronic Locking Differential (ELD) installed in the Ford F-150 is a sophisticated component that serves a crucial role in handling slippery road conditions. Without the ELD, the rear differential is effectively a solid axle, which interferes with its intended function, especially during turns. This represents a significant indication of a malfunction within the rear differential system that requires attention.

Reason: ELD Switch Broken

If the ELD switch is broken, it can prevent the system from unlocking. The switch is typically used to engage or disengage the ELD system, and if it is damaged or broken, it may not send the proper signal to the control module. And this can prevent the system from unlocking.

The ELD system works by using sensors to detect wheel spin and sending signals to the control module to engage or disengage the locking mechanism. If the switch is not working properly, it can prevent the control module from receiving the proper signal. As a result, this can cause the system to remain locked and not unlocked.

Solution: Replace the ELD Switch

Replacing an electronic locking differential switch requires some basic knowledge of car parts and tools. The following step-by-step guide will help you replace the switch:

Tools and Components Needed:

  1. Replacement electronic locking differential switch
  2. Pliers or a small screwdriver to remove clips
  3. Wrench or pliers to disconnect the electrical connector

Step 1: Remove The Old Switch

Locate the switch knob on the dashboard or center console. Next, hold the switch knob and pull it out of its socket. Then find the attachment for the switch at the back of the socket.

Step 2: Release The Clips

Look for the clips that hold the switch in place. There are typically three clips, which you can press in using pliers or a small screwdriver. To remove the switch assembly, press the clips and pull them out of the socket.

Step 3: Disconnect The Electrical Connector

Once the switch is out of the socket, locate the electrical connector at the back of the switch assembly. After that, disconnect the electrical connector by releasing the clip or using pliers or a wrench to undo the connector.

Step 4: Install The New Switch

To install the new switch, start by connecting the electrical connector to the back of the switch assembly. Then, put the switch assembly back into the socket. Make sure the clips line up with their respective slots and push the switch assembly until it snaps into place.

Step 5: Test The New Switch

To replace an electronic locking differential switch, start by turning on the ignition. Then, test the new switch to make sure it’s working properly. That’s all you need to do! For a better understanding, you can also watch a video tutorial on the process.

How Often Should You Change The Rear Differential Fluid Ford F-150?

To keep your F-150 truck in good condition, it’s recommended to replace the differential oil every 30,000 to 50,000 miles. It’s best to have a professional mechanic check the gear oil during regular maintenance. 

This can help prevent problems like wear and tear or breakdowns. Don’t wait until something goes wrong – be proactive and maintain your vehicle’s rear differential fluid regularly. This will ensure your truck runs smoothly and safely on the road.

Can I Drive With A Bad Rear Differential?

Yes, it’s possible to drive with a bad rear differential if it doesn’t stall the car. But, it’s not a good idea to drive like this. A bad differential can make one wheel turn faster than the other, causing issues. 

It can damage the differential or other car parts like the wheel and brake plate if you continue to drive like this. It’s not safe to drive with a bad rear differential as it poses a significant safety threat. Therefore, it’s better to avoid driving with a bad rear differential.


What Happens If The Differential Fails While Driving?

When a differential fails while driving, it can result in several symptoms, including vibrations, noises, and fluid leaks. These issues can ultimately impact the handling and acceleration of the vehicle. Therefore, it is important to consult a certified mechanic immediately if you notice any of these symptoms to diagnose and correct the problem promptly.

Does Differential Affect Speed?

If your car’s differential breaks while you’re driving, it can cause several problems. The most important one is that your car won’t be able to transfer power from the driveshaft to the rear wheels, and it’ll stop moving. Also, a broken differential can make your car slip or lose grip, which can be dangerous and make it harder to control your car.

Is Synthetic Differential Oil Better?

Yes, synthetic differential oil is widely considered to be better than traditional mineral oil due to its superior performance characteristics. Synthetic lubricants have a lower friction coefficient in a gearbox, better film strength, and a better relationship between viscosity and temperature (viscosity index, VI). These properties make synthetic lubricants ideal for use in high-performance applications, where maximum efficiency and durability are critical.

Final Words

Well, this was all about the Ford F-150’s rear differential problems. Hopefully, this will be adequate to resolve your issues. If after performing these resolving methods, the issue persists you should consult a professional automobile expert to get it fixed. 

Thanks for reading!

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William Baldwin

This Is William Baldwin, The Founder & Managing Editor of this website. Me and my team share automotive tips, tricks, and news

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Talha Atta

Talha Atta, a Mechanical Engineer and experienced technical content writer and editor at with a passion for the automotive industry.