Why Are There Metal Shavings in my Transmission Oil? Explained

This message is for the readers looking for a little insight on their findings during a general maintenance fluid change. Being a manufacturer of a transmission component, and also having had our shop with two sides to it, (one side for general maintenance, and one side for performance bolt ons and full project builds) we came across these findings ourselves on both sides of the shop. It just happens. Whether its grandma’s car or a lead foot enthusiast, it would not be uncommon to see a little sparkle in the oil.  Not always, but sometimes and it could be normal or it could indicate trouble. These were discovered in daily driver vehicles without any mods and especially any transmission work or upgrades; so this would also conclude that adding our Limited Slip LSD Conversion kit, would not be related to these findings nor be the cause.

Types of transmissions

Transmissions have wearing parts in them, and that is why they inevitably fail. There are many important components to the transmission whether it’s an automatic, manual, CVT, or EV drivetrain.

Normal shavings?

If you have ever looked at the fluid that comes out of your transmission, you are sure to have seen metal shavings in there at some point. This is usually just a sign of normal wear and tear of harmless shavings, especially if your transmission is running normal, and you’re NOT experience grinding, or noise.

The transmission pan has a built in magnet/s or magnetic drain plug to help pick up these metal particles.

What to look for
How do you know what’s not normal? There are 4 descriptive types of material seen in the oil pan.
Metal shavings, or fine powder even, are usually normal in the bottom of the oil pan. If these shavings are large enough to pick up with your fingers or they are sharp, it’s usually an indication that something is wrong. Look for worn or chipped gear set teeth as this is a common find in some inspections. Even casting slag/material can be found which is just a sign of an imperfect manufacturing process in some of the transmission components.
Black pieces could be a sign of a worn clutch though extremely fine particles would be in most cases considered normal. Especially if these fine particles are found by the magnet showing the magnet is doing its job.
Brass and gold colored flakes are usually discovered after some mileage has been put on the car and could be coming from bushings or thrust washers for example since these are made up of brass.
Possible causes and general maintenance

Over revving of your motor so the fluid does not have enough time to lubricate the moving parts is not good for either the motor or transmission. Late oil changes, or in a few cases we encountered where there were no oil changes had been done at all, can surely be a detriment to the drivetrain components causing thick and sludgy oil build up. Abusive driving like mis-shifting of gears for example would put a strain on the transmission.

Keeping up with your manufacturer’s suggested routine maintenance schedule will help with keeping everything in check. We also recommend for full endurance race type applications, changing your oil after about 20 hours of hard race use. Your transmission and its components including the differential, are not bullet proof. In fact, there are probably some type of documented recalls or even weak parts known to specific transmissions. Consider this when looking into possible causes or helping to give your transmission a longer life.

If you have a question or comment, please don’t hesitate to reach out to us.

 

 

 

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