Keep Your Automatic Transmission Cool!

Posted by on Thursday, July 25th, 2013

The modern automatic transmission is a very complicated piece of hardware. While automatic transmission designs can vary from manufacturer to manufacturer, they all share one common enemy; heat! Excessive heat is by far the automatic transmission’s number one enemy, regardless of the number of gears it may possess.

This is your typical automatic transmission


Here is a very important fact that you should memorize.  Your transmission is designed to work at a maximum temperature of around 200 degrees. For every 20 degrees you go over 200 degrees, you cut the transmission’s excepted life span by a factor of two. In other words, at 220 degrees your transmission will only last half as long as it was originally designed to. At 240 that number drops to ¼ the normal life expectancy. Get up to 260 degrees and that number drops to 1/8th.  At 280 degrees it drops all the way down to 1/16th. Now you understand why it’s so important to keep your automatic transmission cool!

Did you know that at temperatures as low as 240 degrees, your oil based organic transmission fluid can start to turn to varnish? Once this occurs, the fluid loses its ability to properly lubricate the transmission and a total transmission failure is just around the corner.

So how do you keep your transmission from overheating?

-   Don’t drag race your vehicle from light to light.

-   Don’t tow over the vehicle manufacturer’s maximum tow rating.

-   Slow down when going up steep, long hills.

Here is a list of accessories you can add to your vehicle to aid in cooling:

The way you mount your tranmission cooler is very important


Invest in an aftermarket transmission cooler. My advice is to purchase the biggest cooler that will fit your vehicle. Look for what is known as a stacked-plate design. This type of transmission cooler is stronger and more efficient than the typical tube and fin design.  For a little extra insurance purchase a cooler that has a built in fan. Ideally, you want to install the cooler in between the line coming out of the transmission and the return port on the side of the transmission.

Install a deep aluminum oil pan. Most deep pans add 2 -3 quarts of fluid capacity to the system. This extra fluid will go a long way in keeping your transmission cool, especially when the ambient outdoor temperatures rise. The properties of aluminum are such that they dissipate heat much better than steel, so a pan made of aluminum will also aid in the cooling process.

An aluminum pan will help keep your transmission cool


Switch over to a synthetic transmission fluid. Synthetic fluids will hold up much better at high transmission temperatures than organic based fluids. Although more expensive than traditional transmission fluids, you can go longer between oil changes and that alone will help make up the difference in cost.Don’t let your automatic transmission overheat! Take action today and save yourself a headache in the long run.

If  your transmission has just suffered a heat related failure, please consider replacing it with a re-manufactured transmission over one that was simply rebuilt. A re-manufactured transmission will include alterations and upgrades that are designed to make it stronger and more durable. A rebuilt transmission will not.  A re-manufactured transmission comes with a much better warranty - three years compared to an average 90 days for a rebuilt transmission.

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