What Causes Metal Shavings In Transmission Fluid?

Last Updated on September 9, 2023 by Chase Reiner

Metal shavings in transmission fluid are primarily caused by friction and wear on internal components. On average, 90% of transmission failures result from overheating and excessive wear.

What Do Metal Shavings In Transmission Fluid Mean?

What Do Metal Shavings In Transmission Fluid Mean

It means that your transmission is now ready to be rebuilt. However, it could be for any of these reasons:

1. You chose a bad-grade fluid

2. You changed your oil a little late

3. You kept revving up your engine too much. Over-revving prevents the fluid from lubricating the moving parts, which increases the level of wear and tear. The product of the grinding is metal shavings.

However, you should not worry about tiny shavings. That is because there is normal wear and tear, and any mechanic will not sound an alarm if they only see smudge and metallic dust.

But, if the shavings are more, take it up with a qualified transmission mechanic. He will use his competence to check all the components. Since those parts take in a lot of pressure, they need to be set correctly.

Transmission components are not bulletproof, neither are they eternal. Have that in mind as you steer clear of this fluidity issue.

What Causes Metal Shavings In Transmission Fluid?

The discovery of metal shavings in transmission fluid can be quite alarming. This generally indicates trouble within the transmission system of a vehicle. There are several potential causes of this issue that every car owner should be aware of. 

1. Normal Wear and Tear:

With time, most car parts will eventually start to wear down. The minuscule metal particles found in the transmission fluid may simply be a result of the normal operating process. Tiny debris from gears and other parts can break off and contaminate the fluid over time. However, larger metal shavings are a sign of serious trouble.

2. Incorrect Installation of Parts:

When parts are not correctly installed in the transmission system, they may scrape against each other. This excessive friction could cause metal shavings to enter the transmission fluid. Therefore, it’s important to have transmissions serviced by professionals.

3. Lack of Fluid:

Transmission fluid acts as a lubricant, reducing friction between metal parts. If the fluid levels drop too low, metal components will rub together, eventually wearing down and resulting in metal debris in fluid.

4. Broken Gear Teeth:

If you notice larger metal shavings, it could be due to broken gear teeth. This is usually accompanied by a loud grinding or clunking noise when changing gears. It’s a serious issue that necessitates immediate attention.

5. Bearing Failure:

Bearings within the transmission can also fail, especially those present in the torque converter. When these bearings fail, they can disintegrate and cause metal shavings to become prevalent in the transmission fluid.

6. Overheating:

Overheating can be a crucial cause of metal shavings in transmission fluid. When the transmission generates excessive heat, it can cause components to disintegrate, leaving metal shavings in the fluid.

Normal Wear and TearGradual wearing down of transmission system components
Incorrect Installation of PartsParts scraping against each other due to improper fitting
Lack of FluidFriction between metal parts due to inadequate lubrication
Broken Gear TeethResult of the breakdown of larger transmission components
Bearing FailureBreakdown of bearings within the transmission system
OverheatingExcessive heat causes the disintegration of elements

How Does Metal Get In Your Engine?

When any of the moving parts are not lubricated, wear will cause metallic shavings, which will end up in your engine.

Think about it this way. When you are filing your nails, the sharp edges end up as powder. For vehicles, the filling is usually happening at a higher rate. Read these pointers to see an example:

1. An engine running at 3,000 RPM (speed) means all the moving parts are rubbing against each other fast.

2. If the vehicle in question has a 3.5-inch piston, the piston will be traveling around 7 inches on every revolution.

3. Therefore, the 3000-RPM engine moves the piston 1750 feet each minute.

4. Now, imagine if there is only a thin film of oil to cover the piston. That little lubrication will create friction and heat that will melt down the parts.

5. In the end, you have both visible and invisible metal shaving in the engine and all the oils.

Is Metal In Oil Normal?

Yes, if it is tiny and almost invisible.

But, if they are as big as this one, you’ll need to bring in expert help:

How Do You Know if Your Transmission Fluid is Contaminated?

So, you’ve noticed metal shavings, and it’s quite an unsettling sight. Now, you wonder if your fluid is contaminated and if you need to change it at all. Well, this section runs you through the signs of lousy transmission fluid:

1. Dirt In The Fluid

Your transmission oil needs to be in its best quality, so always check it. If your car’s transmission is automatic, pull out the dipstick and look at the fluid. Since consistency is vital, so dip it in, pull it out again, and check it.

At its best, the fluid should be pink-tinted or clear. However, if you see a brown or deep-red color, it is dirty and of low quality. To prevent further damage to the transmission, replace it together with any visible particles.

2. Whining In The Transmission Area

You are reversing your car, and suddenly, you hear a whining noise. Where could the problem be? The noises come about if the fluid line is clogged, meaning that the fluid cannot flow.

If the whining is happening during forward drive, you could be looking at a problematic torque. So, fix it soon because it is a severe problem that could prove costly.

3. Slipping Gears

Dirty and contaminated transmission fluid will get your gears slipping. That’s because it makes a vehicle have little to zero hydraulic power. So with the power down, gear will not stay in place, needing you to put extra effort while engaging them. To fix slippery gears, a change of fluid will work. 

4. Car Not Going In Reverse

A car that refused reverse engagement could be experiencing many problems, one of them being contaminated fluid. The dirt makes it difficult for the fluid to flow, meaning the car cannot switch in reverse. 

5. The Engine Is Burning Up Like Hell

When your car’s temperature goes us, it is hard for you to point your finger at the transmission fluid. But that liquid could be the culprit! Remember that if the fluid does not enter the cooling tanks, the excess heat will flow into the rest of the engine.

You will not like it.

6. Grinding In The Transmission Area

Apart from whining, you are likely to hear your transmission grinding. That indicates that the fluid is dirty, contaminated, and unable to lubricate, as it should.

Will A Transmission Flush Fix My Transmission?

Not entirely.

During transmission flushing, you usually let the old fluid drain out while pouring in the new liquid.

Now, this method isn’t the best because it leaves a residue of the old fluid. Thus, when you add the new fluid, it picks the remains, making it compromised. The ‘contamination’ affects its role, meaning that you will need another flushing sooner than you expect.

If you want to take on this method, consider talking to a pro mechanic. He will run a complete flush and, if need be, clean the transmission line with some solvent. Once the line is clear of debris and remains, the mechanic will pump in the new fluid. 

Why You Should Never Flush Your Transmission Fluid

If you are a fan of flushing, you might want to read these pointers:

1. First, the transmission fluid is like a detergent, so it has cleansing properties. Second, it can varnish off your clutches, causing them to slip.

2. Pressure flushing, which is common in auto repair shops, is likely to cause aging. Also, it makes the seals leak. If the leak is a quart or more, the entire unit can burn.

3. But, flushing does not cause transmission failure, but it exacerbates the process. That is because it pushes metal shavings and particles back, and those are detrimental to the system.

Is it Normal to Have Metal Shavings in Rear End?

From Tacomaworld.com, you will see that, indeed, it is normal to have metal shavings in the rear end. That is true for a new diff, especially one that is straight from the factory. However, once you check the next time, you will not see them much. That is because the oil will be cleaner.

However, if you do not see a lot of change, consider changing the oil there.

Can Dirty Transmission Fluid Cause Shifting Problems?


If the transmission fluid is dirty or running low, you may experience hard shift conditions. So, if you find the fluid looking anything other than clean and light, consider changing it.

How Often Should The Transmission Oil Fluid Be Changed?

For manual vehicles, the change should come after 30000 to 60000 miles. For automatic ones, every 60000 to 100000 miles should be good.

However, it is possible to change the fluid earlier since it cause no harm to your transmission if you change the fluid earlier. Actually, some drivers who put heavy-duty on their vehicles tend to change it after 15000 miles.

The best way is to talk to a trained technician or your favorite auto repair shop. They will give you credible advice, and they can even offer to do it at a cost.


Now, you know that wear and tear is the leading cause of metal shavings in your transmission. While the tiny, almost invisible ones are not alarming, fluid full of metallic debris should worry you. If that is your situation, consider flushing the transmission perfectly to ensure your driving experience is the best.

Before you go for transmission flushing, consider talking to your mechanic. Ensure you know the pros, cons, and long-term effects of such a method. Moreover, change the fluid if you have been driving your vehicle for over 30,000 miles. That will help the vehicle’s performance, and you will be safer on the road.

And we are done!



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