How Much Metal Is Too Much In Transmission Fluid?

Vehicle transmission is as important as the engine. And you need to pay critical attention to this component because it works in unison with the car engine to offer optimal performance, speed, and torque. Without it, the vehicle cannot move. Therefore, it needs to be in good condition at all times.

Most people are confused when they see magnetic shavings in the oil pan when changing the transmission fluid and wonder if it means the transmission is wearing out. The truth is, some amount of metal or magnetic shavings in tranny crankcase is normal and harmless. But how much metal is too much in transmission fluid? I’ll answer that in the next section.

metal shavings in transmission fluid

How much metal is too much in transmission fluid?

Unlike the car engine, you can touch and feel some metal shavings in transmission fluid, and it’s normal. If you look into the tranny oil pan when servicing or changing transmission oil, you’ll see grime, metal flakes, metal shavings, or fragments.

While metal shavings, grime, and fragments are normal in the tranny; metals above 5% in the transmission fluid are too much. Metal shavings, particles, and grimes less than 2% are absolutely normal. If the particles or metal shavings are above 5%, it means some of the internal components are wearing out.

The truth is dirty transmission fluid or too many metal shavings in the tranny will cause noise and hard gear shifting in some cases and lead to further damage to the system components.

What causes metal shavings in transmission fluid?

Your transmission needs the same preventive care and maintenance you give to your engine. The common cause of metal in transmission fluid is a delay in changing transmission fluid or not changing it at all. As a result, the transmission fluid will lose its lubricating properties, causing the gears to grind against themselves.

The grinding will shave out fragments from the internal components and circulate in the tranny along with the transmission fluid. The shaved-out metals in the transmission pan will cause further damage to the unit and you may get bad transmission fluid smell you’re your vehicle. Therefore, you should replace your transmission fluid once the shavings exceed 2%.

Are the black metal flakes in the transmission oil harmful?

Black metal particles in transmission fluid indicate abnormal component wear. Typically, they are worn band friction material or clutch. If the particles are too much, it means you have abnormal wear. It is normal if the black metal flakes are small and centered around the magnet on the oil pan.

The magnet is responsible for collecting metal shavings, flakes, grime, and other particles in the transmission to prevent them from circulating alongside the transmission fluid, which could cause severe issues in the unit.

How to fix metal shavings in transmission oil

What should you do if you find glitter in transmission oil? As explained earlier, small metal shavings in oil are normal. But if you can feel the edges of the shavings by rubbing them with your fingers, it shows your planetary gear sets, clutch packs, and other internal components are wearing off quickly. And the first step to fixing metal shavings in the transmission is inspection.

You should park the vehicle in a solid, leveled, safe spot. Lift the vehicle and support it with your jack stands so you can easily slide underneath it.

Now, slide underneath the vehicle and drain the transmission fluid. After that, loosen the oil pan and inspect it to know the kind of shavings you have. The transmission could have different types of shavings, and each one connotes a specific problem. Here are the types of shavings you should watch out for.

Brass shavings:

Brass shaving means one of the thrust washers or bushings is wearing off. The thrust washers and bushings are made with brass, and they will start wearing off after covering a hundred miles or so.

Metal shavings:

Metal particles in transmission fluid mean the gear sets are wearing off. It could be normal or abnormal wear. Small metal particles are normal. If the metal particles are small, clean it. That could be all you need to rectify the underlying issues.

Black flakes:

As explained earlier, black flakes indicate clutch or band frictional material wear.

Remove the oil filter and wash it with a washing brush and fuel. Let the filter dry before reinstalling it. While waiting for the filter to dry, wash the transmission pan. After reinstalling the filter and the oil pan, change the old oil and ensure it reaches the recommended level.

This should fix the problem, at least for the time being. A transmission is a complex machine, so you don’t have to do more than this unless you are a gearhead.

If you like keeping records, take pictures of metal shavings in the transmission and keep them. If you notice the shavings again, contact your mechanic and show them the pictures you took before the first fix.

Kindly note that seeing any of these metal shavings in transmission fluid is normal. However, the transmission needs urgent attention if the particles are much and you can feel the edges of the shavings with your fingers.

How much does to fix metal shavings in transmission?

Most times, all you need to fix the metal in transmission pan is to do a full transmission flush before replacing the fluid. Luckily, this will cost you between $100 to $250 at a mechanic garage and $70 if you follow the DIY routes. However, If the shavings result from accelerated wear from the internal parts or a sign of a bigger problem,  the repair will cost between $500 to $2500 on average.

Final words

This article has explained how much metal is too much in transmission fluid. Now you know which is normal and which is abnormal. Whether the metal shavings in the transmission are normal or not, always wash off the shavings whenever you open the transmission crankcase. This will prevent the shavings from clogging the oil filter. 

However, if the metal shaving is up to 5%, contact a mechanic to check the transmission and address the root cause before it escalates to major repairs.


Mr. Shafiqule Islam is a graduated Mechanical Engineer and has more than 15 years experience of repairing and maintenance of different brand vehicles like Toyota, Mitsubishi, Ford, Mercedes, BMW etc. He is also giving training to Mechanics. He has started writing to share his practical knowledge to Vehicle Owners, Drivers and Mechanics to keep their cars at best fit.

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