5 Symptoms of A Bad Differential & Replacement Cost

One of the most important components in keeping your car traveling in the right direction is the differential. It’s essentially what maintains your front and rear tires on the same page, ensuring that each set is given the appropriate amount of power to travel in the desired direction. When your differential fails, it might spell disaster for your vehicle.

We’ll go through the signs and symptoms of a faulty rear differential, as well as what causes a rear differential to fail in the first place. Hopefully, this information will assist you in keeping your car differentials in good operating order and warn you when it is time to get them serviced.

symptoms of bad differential

In this article, you’ll learn the 5 common symptoms or signs of a bad differential. You’ll also know how much their replacement cost and some causes and repair options for the rear differential.


Read more: Understanding differential


5 signs or symptoms of a bad differential

The followings are the common signs of a bad differential:

  • Damage to the Tire
  • Reduced Handling Capabilities
  • Vibrations
  • Whining Noises
  • Grinding Gears

Damage to the Tire

It’s a good sign that your differential is failing if you notice sidewall or outer tire wear on the back wheels. When the differential fails, the gears grind, causing the tires to turn at the same rate, causing the tires to wear out.

Reduced Handling Capabilities

When you have a faulty differential, cornering control might become unpredictable, and you’ll notice that the car isn’t performing as it should.


Vibrations that grow in severity as you speed up and decrease as you slow down can be caused by a faulty differential. If you experience this problem, you should avoid driving at high speeds and take your car to a mechanic as soon as possible.

Whining Noises

Hearing whining noises could mean your differential is failing, but this isn’t always the case because it could also be a sign of a broken wheel bearing.

Grinding Gears

Another symptom that your differential is failing and the gears are worn down is the grinding of the gears. In this condition, you should avoid driving the vehicle because the rear wheels can lock up at any time, which is unsafe.

What Causes a Rear Differential to go Bad?

Let’s begin by identifying the source of the problem. What goes wrong with a rear differential?

One of the most common causes of a differential failure is the manner a new car is driven. There is a grace period during which your automobile must be ‘broken in,’ and overworking your engine too quickly can result in front or rear differential noises that indicate a larger problem.

We mean driving too quickly (above 50 mph) for lengthy periods, or towing or hauling another thing, such as an RV or a boat. Your differential may overheat and begin to fail as a result of this.

Allowing your automobile to spin out a lot is the simplest method to cause problems with your differential. Spinning out unintentionally now and again shouldn’t do too much harm. However, if your front wheels stay on the road while your back wheels fall out, it might be dangerous. These kinds of actions have the potential to break or ruin components of your differential.


Read more: Understanding Limited Slip Differential


What are the Repair Options for a Rear Diff?

The followings are the common repair options for a rear differential:

  • Gasket Replacement
  • Bearing Replacement
  • Sealing the Piston and Side
  • Replacing the Rear Differential Entirely

Gasket Replacement

Rubber or silicone rear-diff covers are common, although they can wear and dry out over time. You’ll need to have them replaced to keep them from leaking. Fortunately, this is a quick fix that shouldn’t take more than an hour to complete.

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Bearing Replacement

In a differential, there are two bearings: one for the pinion and one for the side. You’ll need to replace one or both of them once it starts to grind or hum. Because this involves disassembling the differential, it can take up to 5-hours to accomplish, making it significantly more expensive.

Sealing the Piston and Side

If you observe a puddle of fluid under your vehicle, it’s possible that the piston or side has to be sealed. Both need a significant amount of time to repair, particularly the latter, which necessitates the removal of the axle shafts.

Replacing the Rear Differential Entirely

If none of the following fixes works, your rear differential may need to be replaced totally. This is the worst-case scenario, and it usually indicates the diff gears are useless.

How much does it cost for differential replacement?

The average cost of a complete rear differential replacement is between $1000 and $4000. Fortunately, you may simply repair it or replace it with a used differential, which will drastically reduce your costs.

The majority of differential fixes will cost between $200 and $400. Of course, the severity of the issue and the parts that need to be replaced will determine this.

You may need to spend between $400 and $1,000 on a rebuilt differential. On the other hand, replacing a differential costs $1,000 to $2,000 on average. Most people will not be able to complete this task without the assistance of a qualified technician.


Read more: Understanding powertrain and drivetrain


How do you properly replace a differential?

Changing the differential fluid every 30,000-50,000 miles is the best way to extend the life of your rear differential. You should also have your drivetrain inspected once a year. As a result, any repairs will be easy rather than requiring a complete differential replacement.

Watch the video below to quickly learn how to replace a differential:


The differential is another great component in an automobile as it helps vehicles to travel in the right direction. imagine it going wrong, then you can start to think bad about the risk and safety. That is all for this article, where the common symptoms of bad differential are being discussed. Some FAQs are also explained such as the replacement cost, causes, repair options, and how to replace a differential are being discussed.

I hope you learn a lot from the reading, if so, kindly share with other students. Thanks for reading, see you around!