What are the Bad Pinion Bearing Symptoms?

Vehicles make mobility easy for us. However, to continue enjoying the benefits of possessing a car, it is essential to understand its maintenance; otherwise, not understanding bad pinion-bearing symptoms and other faults can lead to a disaster in your vehicle.

Unexpected breakdowns of vehicles do not suddenly occur; there are usually noticeable symptoms before any sudden breakdown. If you notice signs of a faulty part of your vehicle, you should seek the attention of a professional mechanic to fix the problem.

Driving with a bad pinion bearing can be frustrating; from the whirring sound to the damages it causes on the differential, driveshaft, and transmission in your vehicle are all signs of a worn-out pinion bearing. 

If you are wondering, “What is a pinion bearing?” and the signs to look out for in a bad pinion bearing, this article is to expose what it feels like to drive a vehicle with a bad pinion bearing.

what is a pinion bearing

What is a Pinion Bearing?

A pinion is a round gear, usually the smaller amongst two meshed gears, used in various applications, such as drivetrain and rack and pinion systems.

The rack and pinion gear set perform two primary functions: the reduction of gears, which enables the steering wheel to turn the wheels easily, and the conversion of the steering wheel’s rotational motion into linear motion, which helps the wheels of the vehicle turn easily.

A pinion bearing helps the smallest gears in the differential work efficiently. Differentials consist of a series of cogs and gears, and it is the smallest gears that enable one wheel to rotate faster than the other safely. Meanwhile, the pinion nuts help to hold the pinion gear and the driveshaft yoke together securely.

What are the Bad Pinion Bearing Symptoms?

The following are noticeable signs of a bad pinion bearing in a vehicle.

Whirring Noise: One of the pronounced bad pinion-bearing symptoms is its whirring noise during acceleration or deceleration at various speeds. Worn out pinion bearings create more whirring noise rather than rumbling because it rotates several times faster than the carrier assembly of the vehicle.

Vibrations: Vibration is one of the pronounced signs you can easily notice. Worn-out pinion bearing results in noticeable vibration or differential noise on acceleration.

Gear grinding: Gear grinding or humming noise is another symptom that reveals a bad pinion bearing. The gear grinding is produced in the process of acceleration of the vehicle.

Tire damage: Tire damage is also one of the bad front pinion-bearing symptoms. Due to the higher speed of the inner tires, which is more than what the inner thread can sustain, the vehicle tires tend to wear out or get damaged in taking corners with the wheels and tires traveling at the same speed.

What Causes Pinion Bearing Failure?

Pinion bearing failure is traceable to some of the following causes.

Failure from Lubrication: About 80 percent of pinion bearing failure is traceable to inadequate lubrication. Sometimes, it could be insufficient lubrication, inappropriate lubricants, or degradation of lubricants due to excessive temperature.

Corrosion: Corrosion is another cause of pinion-bearing failure. Corrosion could result from acid, moisture, broken down or low-quality grease, etc.

Contamination: The entrance of unnecessary/alien substances such as dirt, dust, abrasive grits, etc., can contaminate the pinion bearing, resulting in its failure. 

Misalignment: Misalignment can result from bent shafts, out-of-square clamping nuts, out-of-space shaft shoulders, out-of-square spacers, and improper installations. This error can lead to overheating and separator failure.

Improper Mounting: Pinion bearings should be mounted with a press on the floating ring. Mounting bearings on shafts by applying blows or pressure on the outer race, poor finish on the bearing seat, etc., can result in pinion bearing failure.

False Brinelling: False brinelling results from lack of rotation in the bearing, which disables fresh lubricants from returning to the spot, and a rapid movement of the balls while the vehicle is idle.

Fatigue: Overloading, excessive preload, the tight inner ring fits, and excessive bearing above lifespan can result in fatigue, which later results in pinion bearing failure.

Overheating: Improper lubrication and excessive temperature can cause overheating. High temperature can cause loss of lubricating oils from grease, resulting in dryness that causes the bearing to seize.

Excessive Loads: Exerting too many loads than necessary on a bearing can also cause pinion bearing failure.

Important Tips and Tricks for Long-Life Pinion Bearings

Understanding the causes of pinion bearing failures and the symptoms of bad pinion bearings is a significant advantage for ensuring long-life pinion bearings. However, you don’t have to wait until you observe the symptoms of your bad pinion bearing. It is better to take preventive measures to ensure that your pinion bearing lasts longer.

The following are some essential tips and tricks for long-life pinion bearings.

Proper lubrication: It is essential to use the appropriate or recommended lubricant for pinion bearing to ensure its longevity. Avoid loss of grease and pay necessary attention to recommended intervals for an oil change.

Careful mounting: Endeavor to follow proper mounting instructions provided by your vehicle manufacturer or vehicle experts when mounting bearings.

Keep corrosive fluid away: Ensure to keep corrosive fluids, such as acid, water, etc., away from the bearing area to avoid corrosion.

Reduce loads: Ascertain the maximum amount of load the pinion bearing can carry and stick to it, or use a bearing with greater capacity for loads.

Carefully store bearing before use: Make sure you store bearings in a dry environment at room temperature. Ensure to cover bearings to keep them clean during storage. Do not unwrap to expose until you are ready to use, and then move them to the installation site when they are ready for use.

pinion bearing replacement cost

Frequently Asked Questions – FAQs

Q: What happens when a pinion bearing goes bad?

When a pinion bearing goes bad, one foremost occurrence is the noticeable whirring noise it produces, vibrations, gear grinding, and tire damage.

Q: How much does it cost to replace a pinion bearing?

The replacement of a pinion bearing would cost an average of $239 – $286. Parts are estimated to cost about $66 – $68, while the labor costs would be around $173 – $218.

Q: What noise does a bad pinion bearing make?

A bad pinion bearing makes a whirring noise at all speed levels, during acceleration or deceleration. Instead of rumbling, a bad pinion bearing whirs due to its turning speed, which is a lot faster than the carrier, depending on the gear ratio.

Q: What does a bad rear axle bearing sound like?

A bad rear axle bearing produces a loud clanking, clicking, or clunking sound when you put your vehicle into gear. These sounds are usually produced on the side with the faulty axle bearing, and the sound increases whenever you try to make a fast or sharp turn.

Q: How do you remove a pinion bearing? 

If you are experiencing differential backlash symptoms or signs that your pinion bearing is worn out and you need to remove a pinion bearing, the following steps can make the process easy for you.

Step 1: Lift the vehicle with a four-post or two posts lifter, as the case may be. Lose the propeller and the flange. Remove the wheels and the rear axles.

Step 2: Use a cutoff tool to cut the pinion-bearing cage. Then remove the cage and the bearings. After that, carefully cut a channel in the inner race, which is pressed on the carrier, while ensuring not to cut into the carrier so that the process is not damaged.

Step 3: Put a chisel in the channel you have created by the cut. Then strike it with a big hammer so that the inner race can break. The inner race will either loosen and fall off or break off immediately, depending on the force exerted on the chisel. However, you should do it with care.

Step 4: Get a two-by-four block of wood, place the opposite end of the carrier on the block of wood, install the new bearing on it as far as necessary manually, and ensure that the placement is straight enough.

Then drive the bearing on with the pipe and the big hammer. Hit it down until everything fully sits on the inner flange.

This video can help you further understand the process of removing a pinion bearing.

Q: How do you fix a loose pinion bearing preload?

If you are experiencing loose pinion-bearing preload symptoms, simply remove shims in order to tighten the bearing against the races and then increase the pinion-bearing preload.

Final Words

Why should you risk total damage to your vehicle when you can easily ascertain bad pinion-bearing symptoms? This article has exposed the need for you to carry out adequate maintenance or repair on your vehicle when necessary. The causes of pinion-bearing failure and its symptoms have also been dealt with.

Now, you may not have to ask, “How do you know if your pinion bearing is bad” anymore. You need to examine your vehicle whenever you find any of the symptoms discussed above and then take necessary measures to rectify the problem by changing the bad pinion bearing.

Osuagwu Solomon

Osuagwu Solomon is a certified mechanic with over a decade of experience in the mechanic garage, and he has over five years of experience in the writing industry. He started writing automotive articles to share his garage experience with car enthusiasts and armature mechanics. If he is not in the garage fixing challenging mechanical problems, he is writing automotive repair guides, buyer’s guides, and car and tools comparisons.

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