John Nielsen: Hi! I'm John Nielsen with AAA Approved Auto Repair. Maintaining the fluids in our vehicles engine is critical to protecting our investment in the long run.

Now automatic transmission fluid is gone through a number of changes in recent years, gone are the days when they were simply two types of fluid on the market. Many of today's manufacturers use a proprietary automatic transmission fluid and it really is imperative that you use the right fluid to get not only a good shift quality and a comfortable ride, but to protect the warranty in your transmission.

So let's talk for a minute about how to check the automatic transmission fluid in our vehicle's transmission.

Most cars use a dipstick much like the oil dipsticks, where you'll simply start the engine and with the engine running, remove the dipstick, clean it off, reinsert, pull it out to check the level. Make sure you do it on level surface and if the transmission fluid is low, it needs to be topped off with the fluid that's recommended in your owner's manual.

Now some cars don't even use a dipstick anymore, so checking that owner's manual is going to keep you from fumbling around under the hood of the car looking for something that doesn't exist. Now on those transmissions that don't have a dipstick, there really is no way to check the automatic transmission fluid and the manufacture counts on you changing it at the proper interval.

So how often should you change the automatic transmission fluid, once again that's in the owner's manual and typically, it's going to be sometime around three to five years depending on the application and how you used our vehicle. Some trucks can be as often as 25,000 miles when towing heavy.

But it really is important that you change the fluid according the manufacturer's recommendations then you change the filter, when you change the fluid to keep your transmission operating properly, protect your investment for the long run, and oftentimes protect your warranty.