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Secondary Transmission Filter and Cooler to Prevent Transmission Problems


Ever have transmission issues with your car? I started having transmission problems with my car recently. Although my car isn't new anymore, but I also have a car that is older and transmission problem free. The problem usually starts when the gears starts to slip, meaning you'll hear the car rev as it tries to switch gear. As the transmission starts to wear sometimes you'll get somewhat of a "smooth" gear change, but in fact it might be slipping into the next gear, but the hesitation is minimal. The most common reason is usually the metal shavings in the transmission which starts to act as friction material. As vehicles get older it is advised to change the transmission fluid with every 3rd oil change. There are many symptoms when the transmission starts to go. The transmission fluid must be able to maintain a certain temperature because when oil heats up, it will not be able to perform as well as it should. Some people add a secondary cooling system for the transmission fluid to cool better.

Transmission fluid must be maintain, although some people would argue that the transmission fluid should not be touched, just think of it like this, transmission fluid does have certain detergent that helps loosen grime or gunk from the transmission to keep contamination at a minimal. The contaminants are small, but when enough gather at a certain part of the transmission it will cause heat and in doing so will cause the transmission to overheat.

Symptoms for transmissions issue but not limited to

  1. Slipping as the gear is changing
  2. Hesitation when accelerating from a full stop
  3. Rough idle in neutral
  4. Loud humming or clunking noises
  5. Smell of burnt fluid

All this can also be symptoms of other issues as well. Usually a check engine light would be present if the transmission has a problem but some problems are known not to trigger the light. Certain problems such as the throttle positioning can also give similar symptoms. When we had a problem in our car we went through almost every part before rebuilding the transmission itself. Cleaning and replacing parts will help but if the main problem isn't fixed then the problem will persist and eventually come back.

The difference I have come to realize was that our older vehicle, which is the same make and model except different year, was that I had placed a secondary transmission filter, and having a secondary filter helps keep the car transmission clean to prolong it's life. Sixth generation Accords seem to be prone to transmission issues due to heat and low rpm gear change when driving in D4, the third gear is frequently engaged during stop and go traffic, 1->2->3->4 then 4->3, 3->2. There's no prejudice to what brand of car make or model will be affected. We'll briefly take a look at some transmission coolIng system later in case you may feel you need it. The amount of money spend to protect your car against the amount to rebuild a transmission is enormous, for this reason alone it is worth protecting your vehicle and you can spend the rest elsewhere or just save it.


After my rebuild on our 1999 Accord transmission we decided to add a secondary filter as well. The brand we use is Magnefine. It contains a filter as well as a magnet to filter out as much contamination as possible. The connection or installation is fairly simple, provided you know what you are looking at, from the radiator you have the transmission fluid passing through to be cooled off and back into the transmission. The filter is usually installed on the return line and if there is a secondary transmission cooler, then it can be put in before the second cooler. Some may put it elsewhere, but reason for putting it before the cooler it's because the fluid would in theory cool off better without contaminants. I had installed the cooler after the radiator and the filter after the second cooler.

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When you purchase these filters, just keep in mind that they do have different hose sizes to fit different vehicles but all that can be found online. Typically the hoses are 1/2 3/8 or 5/16, if you really have trouble finding the right size then you should probably have a local mechanic tell you and it should be free because there isn't any work to be done unless they install the filter for you.

Cooler Kit

A second cooler kit install for the transmission will help the fluid cool down a lot faster, remember the more power the car has the more heat it will generate. The second cooler just acts as the transmission's personal cooler to assist the radiator to do the job better, it does not hinder the flow of the fluid. The Magnefine along with a cooler kit will almost ensure that your transmission will last longer then without it. Having a car with almost 1k horsepower and its been almost 12 years and no sign of the transmission giving up on me is a good sign. I don't usually write these type of articles but because I had helped a few people install it, compare to those without it, the difference in power after long drives is noticeable. When the transmission fluid is too hot the car would lose power, the lubrication of the fluid isn't as affective causing higher friction wear.

Magnifine transmission filter

Magnifine transmission filter

Hayden transmission cooler

Hayden transmission cooler

Brand or No Frills?

As far as brand goes, I had tried all of them or almost all of them, even those with no names. A filter and a magnet placed in the right areas and no fluid restrictions with the ability to clean majority of the contaminants is what we care about. Who makes it or what brand really doesn't matter. The widely used brand where you can usually get 2 filter for the price of one is the Magnefine. The filters are changed when you do a transmission fluid change and that is something you should refer to your manual for the amount of miles to do the oil change.


I can't reiterate this enough, spending a little money to keep your car's transmission going is important. This is to prevent further problems from happening or if you already have transmission issues then at lease prevent it from getting worse as you work on fixing it. A car is like a person, treat it well and it will treat you well, neglect it and it'll probably leave you on some road somewhere. Also keep in mind, no matter how well you care for something, if you tend to abuse it, it will not last long and the whole point to this is to try to keep what you have lasting. We'll just show one more video about installing the filter, there is more then one way to do the install but this is to give you an idea on how to do it. If you have no idea after watching it then you'll probably be better off letting your local autoshop do it for you for a small price. The cooler kit you might need to have it done professionally, it is also easy but it isn't like the filter where you are just leave it hanging. The cost should be fair and the job should be quick, probably about 30 mins to an hour to get it done and have you back on the road.

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