Clogged Transmission Filter: Best Ways To Fix It

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Knowing the symptoms of clogged tranmission filter is helpful for car owners who have noticed this problem.

Bad Transmission Filter Affects the Car

The signs and symptoms of a faulty filter vary from strange rattling sounds and weird noises to the sudden breakdown of your vehicle while driving. This article will help you identify all the possible signs of faulty transmission filters.

What Are the Causes of a Faulty Transmission Filter?

The causes of a faulty transmission filter (or strainer) range from burnt/leaking fluids to rattling sounds and rough shifts. In worse cases, the car may even break down. You should have your filter checked whenever you notice a combination of two or more of these symptoms.

– Fluid Leakage

Bad/blocked transmission strainers can cause leaks in your car. If you find your transmission fluid leaking (especially when you park your car at a spot), chances are high that your filter is to blame. If the transmission fluid, also called gear oil, isn’t flowing through the filter as it should (due to debris and dirt), some of it will get forced outside of the vent tube, and you’ll see this as leaks every time your car stays in one spot for a while.

Although bad strainers are a key cause of leaking fluids in a vehicle, other transmission system components (like gaskets and seals) can also cause this issue. When these components get worn out or defective over time, they end up causing fluids to leak.

Leaking transmission oils can cause severe damage to the gear/transmission system. It’s best to check your filter whenever you notice this problem. If it checks out all right, this issue may be caused by damaged gear parts. Ensure you take your car to a reputable auto repair shop.

– Dirty or Burnt Transmission Fluid

A dirty or burnt transmission fluid is a strong sign that your filters are blocked. This burnt fluid happens because the transmission components are overheating. As a result, they make the fluid used for transmission (gear oil) dark or burnt.

To check the state of your transmission/gear oil, leave your car in neutral, open the bonnet, and locate the transmission oil dipstick. Remove the dipstick as you normally would when checking the transmission oil level. Observe how the oil looks. If you find dirty transmission oil in your car, quickly clean up the oil filter, drain the current oil, and fill your engine with a new one.

The average cost of changing transmission oil in a car ranges from $230 to $475. The actual price will depend on the type/quality of fluid required by your car and the charges from your car mechanic. You will spend less if you DIY.

– Brightened Warning Lights

Brightened warning lights will let you know if you have a bad filter. Most modern vehicles have a Transmission Control Module (TCM), a feature that tracks the performance of the transmission system. Whenever the TCM detects any anomaly caused by a bad/blocked transmission strainer, it switches on your device’s check engine light and displays a trouble code.

Bad Transmission Filter Reason

If your vehicle has this feature and it activates one of the trouble codes related to oil filter blockage, don’t ignore it. Inspect your filter and clean/flush it. It isn’t advisable to drive with a blocked transmission oil filter.

Doing so will only lead to further transmission problems that will cause even more damage to your car. You will then end up spending more money to fix the problem.

– Smoky Smell

If you notice a smoky smell coming from your car, it could very well be that your filters have gone bad. When your filters are blocked, the transmission oil doesn’t flow through them as it should, so the various components of the transmission system run dry. These fluid-starved components get really hot and may burn off the little transmission fluid they get. The burning fluids are what produce the smell.

If you ever perceive the smell of something burning while driving, and you’re 100% sure it’s coming from your car, quickly check the transmission fluid level. If it is up to the required amount, inspect your filter to see if it’s blocked. Otherwise, see a mechanic.

– Unexplained Rattles, Buzzes, and Whines

A strange rattling sound from your car could mean your filters are faulty or clogged. This happens because the fluid that should have flowed through the filter to the working components of the transmission system has been blocked. Besides clogged filters, rattling noises can also arise from other things like a bad catalytic converter, loose engine parts, and faulty drive belts.

In addition to rattling sounds, a faulty filter may also cause whining, buzzing, or whirring sounds when you shift into gear. If your car features an automatic transmission system, you’ll notice a high-pitched whine, especially when parking or reversing.

You shouldn’t conclude immediately that a blocked transmission strainer is responsible when you hear rattling or whirring sounds from your car. But if you are certain none of your other suspicious car/engine parts have any problems, then you might want to see if your strainer is blocked.

If you aren’t sure which part of the car parts to suspect, check your vehicle’s warning lights (if they’re blinking) to get a hint, or see a mechanic. Your mechanic will accurately detect the cause of the sound and change your filter if need be.

– Weird Noises When Car Is in Neutral

A noisy neutral is one major sign of a bad filter. A car suspended in neutral should be almost silent. If it isn’t, there’s a problem; most of the time, it is your transmission oil. Quickly change your transmission oil and clean your filter whenever you notice this issue.

– Rough Shifts

Rough shifts are one of the common signs of clogged/blocked transmission filters in a vehicle. When the filter of your car is clogged, it makes the transmission shift harshly when engaged. Rough shifts are characterized by heavy thuds when changing gears, making passengers uncomfortable.

If you continue driving without fixing the issue, the continuous rough shifts can lead to premature wear or damage to the transmission components. This will cause even more severe problems in the future and cost you even more money.

Fixing a blocked transmission filter will cost between $100 and $400. The transmission oil will be changed during the installation of a new filter, and you have to pay your mechanic too. If you’re replacing the filter yourself, expect to spend between $80 and $200 for new oil and filter.

– Your Vehicle Suddenly Halts

If your vehicle suddenly halts while you’re driving, it’s a strong sign that you have a blocked transmission strainer. One thing you can do to be sure is to try to start the car again. If it stalls again, then your car’s filter may be clogged.

Bad Transmission Filter Solution

The causes of clogged transmission filters are dirt and debris. As you drive your car, dust and debris, accumulate in the filter over time. These accumulated particles will eventually cause a blockage that prevents the proper flow of the transmission oil.

How To Fix Clogged Transmission Filters in Your Car

To fix clogged/blocked transmission filters in your car, you have to locate the filter under the hood of your car, remove it, and clean it. If the filter is bad, replace it. You can also see a mechanic and get the filter fixed or changed for a small fee.

– Find Where the Filter Is Located

The first thing you need to do is locate the oil filter under the hood of your car. The actual location varies from vehicle to vehicle, but transmission strainers are usually located above the transmission pan, close to the area where the engine and transmission meet.

– Take Out the Drain Plug

Before removing the oil filter, you must remove the drain plug first. To do this, loosen the plug using a wrench, turning it anticlockwise. Once the plug is relaxed, pull it out with your hand and let the oil drain out. This step is crucial because you can’t use an old transmission oil with a new filter.

– Take Out the Transmission Filter

The next thing to do after removing the drain plug is to remove the filter. You must undo a few screws or nuts to free the transmission strainer. Once it’s free, take it out and remove the o-rings as well.

– Clean the Filter

To clean your filter, unscrew the top and remove the filter element. Soak it in any cleaning liquid of your choice (for instance, gasoline or soap and water), allowing it to sit for at least five minutes.

Finally, shake it vigorously and dry it out in the open air, or use an air compressor for quick drying. Note that not all air filters are reusable. Sometimes, you just have to change them altogether.

How to Change a Bad Transmission Filter


Now you know all the major signs and symptoms a blocked transmission oil filter will exhibit.

Let’s go over the major points as a reminder.

  • The signs and symptoms of a blocked transmission strainer/filter include the sudden halt of your vehicle, weird noises and rattling sounds, transmission fluid leaks, rough shifts, smells, and dirty or burnt transmission oil.
  • A combination of two or more of these signs is a strong indicator that your filter needs to be checked. Sometimes, your engine warning lights will also give you a hint.
  • To change your filter, locate it (it’s usually above the transmission pan), remove it, open the top lid, shake it in a cleaning solution (gasoline or soap and water), and air dry it.
  • Always change your transmission oil when changing transmission strainers.
  • Not all filters are reusable. Sometimes you just have to see a mechanic to replace it for you. This may cost you anywhere between $100 and $400.

Leaving your filters blocked (ignoring the problem) can be consequential, as it can cause further damage to your car’s transmission system. Always act fast when you come across this problem.


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