Draining and replacing your automatic transmission fluid is an excellent way to help extend the life of your car's transmission. While many manufacturers may not recommend this service as part of their routine maintenance plan, it's nevertheless a critical part of long-term maintenance. However, it's also crucial to choose the proper fluid for your car.

Unfortunately, choosing the correct transmission fluid can be more confusing that selecting a motor oil. Many types of transmission fluids exist, and each fluid may meet different manufacturer standards. While any reputable transmission shop can help you select the best fluid for your car, you'll still want to keep these three crucial considerations in mind as you make your selection.

1. Transmission Type

There are a surprisingly large number of different transmission types on the market. While traditional automatics are still common, you're also likely to find continuously variable transmissions (CVTs) and dual-clutch transmissions (DCTs). Of course, some manufacturers also still produce manual transmissions, especially for sporty vehicles.

Knowing the transmission type in your car is crucial since each type requires specialized fluids. For example, CVTs require fluids that help maintain proper friction on their belts. Meanwhile, traditional manual transmissions typically require something closer to standard gear oil since they don't rely on transmission fluid for hydraulic action.

2. Manufacturer Specifications

Individual automakers release their own specifications for automatic transmission fluid. You'll usually need to select a transmission fluid that meets the specifications used by your vehicle's manufacturer. The three most common specs in the US are Dexron VI, Mercon V, and ATF+4.

Your vehicle's owner's manual should tell you the requirements for your specific transmission. If in doubt, consult with an experienced transmission shop to determine the correct option for your car. Using a fluid that doesn't meet your manufacturer's specifications can cause increased wear, poor performance, or significant internal transmission damage.

3. Fluid Life

While older vehicles often included replacement intervals for transmission fluid, many automakers are now including "lifetime" fluid in their vehicles. Unfortunately, these fluids rarely last the car's lifetime, but owners may be left scratching their heads about the actual life of their fluid. In many cases, it's a good idea to replace these lifetime fluids before the 100,000-mile mark.

As with many other decisions relating to your transmission fluid, it's safest to discuss your options with a mechanic familiar with your car. They can tell you how long your fluid is likely to last under typical usage conditions, allowing you to plan the best time to drain and replace your old fluid.

For more information on automobile transmission fluid drain, contact a professional near you.