Many of today’s vehicles have automatic transmissions that don’t require regular adjustments.  The owner’s manual for many of these vehicles even suggest that you may go as high as 100,000 miles before it is necessary to change the transmission fluid.  All this makes it sound as though your automatic transmission is almost maintenance free.  Unfortunately, this is not entirely true.  For best results, have your transmission fluid and filter changed every 2 years or 24,000 miles.  Be sure to use the type recommended by your vehicles owner’s manual.

The purpose of automatic transmission fluid is to clean, lubricate, cool and protect your vehicles transmission.  It also transmits force and pressure required to keep your transmission operating effectively when you drive.  Its final purpose is to prevent varnish build-up in the transmission.  

Most transmission failures are heat-related as transmission fluid quickly breaks down when exposed to high temperatures.  Several situations could result in enough heat to shorten the life of transmission fluid.  A few of the situations include; towing a trailer, driving up and down mountain roads, sudden starts or stops and spinning wheels in slippery road conditions.

The same reasons that may shorten the life of your vehicle’s transmission fluid will do the same to your transmission filter.  This filter prevents contaminants such as metal chips from gears and bushings and fine material from normal wear from entering the hydraulic system where they can cause increased wear and tear. 

When changing the transmission fluid, it is a good idea to flush the transmission.  This will remove more contaminants than just draining the fluid.  If you’re doing this or having someone do it, be sure the transmission pan is removed in order to change the filter before refilling it with new fluid.  If a new filter is not installed, any contaminants from the old fluid or those removed from the transmission during the flushing process could impede flow through the filter and lead to transmission problems.