How to Detect and Replace a Faulty Transmission Filter

February 17, 2012

Find out about the 4 symptoms that suggest the transmission filter needs replacement, and learn how to replace the filter yourself.

Auto Transmission Detail

The transmission filter keeps contaminants out of the transmission fluid. There are a number of problems that can arise with the filter, which reduce its ability to do its job properly. Being aware of the signs to look out for will give you an idea of when it is necessary to undertake a repair.

Noise
If you hear a rattling that cannot be explained in any other way, checking the transmission will be worthwhile. If a defect has developed, it will need to be replaced or fasteners will have to be tightened. Where the filters become blocked with debris, this can also be the cause of noise.

Leakage
In the event that the transmission filter is not fitted properly or there is a defect to the transmission itself, it could result in leakage. There are a number of seals and gaskets in place as part of the transmission, which can develop cracks that cause a leak. Similarly, if they become dislodged or misaligned, a leak can also result. You will find that signs of leaks will be left behind after the car is moved from where it has been parked.

Contamination
The purpose of the transmission filter is to keep contaminating particles out of the transmission fluid. If the filter fails to do its job properly, the transmission fluid will quickly reach a point where it is too dirty to do its job efficiently. Where the contamination reaches a certain level, it can burn and lead to transmission repair being required. Check the transmission fluid regularly, not just for its level, but to see if it is clean.

Inability to Change Gears
If you find that you are unable to change gears easily or it fails to work at all, a problem may have developed with the transmission filter. Similarly, if the gears grind for no reason or the vehicle surges when the gears are changed, the problem may be as a result of a faulty transmission filter.

Burning Smell or Smoke
Where the filter has become blocked with particles that it is designed to limit, it can result in a burning smell. In extreme cases, it can result in the scary sight of smoke being emitted from the engine.

Transmission Filter Replacement

Most car manufacturers recommend that you change the transmission filter every 30,000 miles or every two years--whichever comes first. When changing your transmission filter, you'll change the transmission fluid and transmission pan gasket as well. Replacing these items is very easy and can be completed in about an hour.

What You Will Need

  • A new transmission pan gasket
  • A new transmission fluid filter
  • The transmission fluid recommended by vehicle manufacturer
  • A car jack and jack stands
  • A socket wrench set
  • A flathead screwdriver
  • Gasket seal adhesive
  • Shop towels
  • A putty knife or scraper
  • A bucket or plastic container

Jack up the Vehicle
Using your carjack, jack up the vehicle and place it on jack stands. This will keep the vehicle secure while you are working underneath it.

Drain the Transmission Fluid
Place your bucket or plastic container directly underneath the transmission drain plug. Use your socket wrench to remove the drain plug and allow the transmission fluid to completely drain into the plastic container.

Remove and Clean the Transmission Pan
Remove the bolts from the transmission pan and remove it completely from the transmission. Remove the old gasket seal from the pan and discard it. Use your putty knife or scraper to scrape any debris around the edges of the pan where the new gasket seal will be applied. Use the shop towels to clean the residue left by the old transmission fluid and remove any dirt and debris that may have built up in the transmission pan.

Install the New Pan Gasket Seal
Apply a thin layer of gasket seal adhesive to the gasket and apply the new gasket to the transmission pan.

Remove the Old Transmission Filter
Remove the bolts that hold the transmission filter in place or use a flat head screwdriver to simply pry the old filter out. Some filters are attached with bolts and some are snapped into place with retaining clips.

Install the New Transmission Filter
Install the new transmission filter in place of the old one and secure with bolts or snap into place with the retaining clip.

Reinstall the Transmission Pan
Attach the transmission pan to the transmission and tighten the bolts and plug securely.

Add Transmission Fluid
Add transmission fluid recommended by your vehicle manufacturer to the vehicle. Make sure to add enough to bring the fluid level to full when the vehicle is running. Use the transmission fluid dipstick to check the level of the fluid.

Dispose of the Old Transmission Fluid
Take the container of old transmission fluid to a recycling center or dispose of it at your local auto parts store. Never pour transmission fluid down the drain or onto the ground, as this can cause environmental problems.

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