(Updated on April 22, 2020)
The transmission relies on lubricant the same way that the engine does. The difference is that the transmission uses a certain fluid made for lubricating its components while the engine needs oil as its lubricant. Like the engine, the transmission’s components need to stay lubricated to keep working properly. If there was ever a fluid leak or the wrong type of fluid in the transmission, then the gears and other metal components would heat up and cause problems for the entire system.
Checking the transmission fluid is an important skill to learn. That way, you will know if it is going bad or if there is not enough fluid in the transmission. But there are different ways to check the condition of the fluid in an automatic transmission versus the fluid in a manual transmission. If you only have experience checking the fluid’s condition in one of these types of transmissions, then you will need to educate yourself on how to check the condition in the other type of transmission.
Automatic Transmission Fluid Check
The condition of the fluid in your automatic transmission should be checked in 40,000-mile increments. Although, your owner’s booklet might tell you to check it after a different number of miles. Do whatever your manufacturer recommends because they know best.
As for checking the condition of the fluid, the first thing you will want to do in an automatic transmission is to check the level of the fluid. A dipstick can be used for this just like when checking the level of your engine oil. In the automatic transmission, the fluid level should rest in the middle of the “full” and “add” marks. That indicates the fluid is at a normal level. On the other hand, if the fluid is too high or too low, you should simply drain all the fluid out and refill it with new fluid at the appropriate level.
Another thing to notice about the fluid is its appearance. If the fluid is bubbly or foamy then you either have the wrong fluid type in there or you have too much fluid. Also, if the transmission fluid appears to be brown at all, then coolant probably got mixed in there and contaminated it. This can happen from a radiator leak in its oil cooler.
Manual Transmission Fluid Check
Car manufacturers will all tell you different figures regarding how often to change your manual transmission fluid. Some manufacturers will say every 15,000 miles while others will say between 30,000 and 60,000 miles. Just look at your owner’s manual to know for sure what the appropriate amount is for your vehicle. One way to know it is time to change the fluid is if you have trouble shifting gears. You may also hear strange noises that sound like grinding coming from the gears. This could mean you don’t have enough transmission fluid or it has gone bad.
Like always, use a dipstick to test the level of the fluid in the transmission. You should also pay attention to the smell and color of the fluid. If it has a burning odor or darker color, then you need to replace the old fluid with new fluid. Otherwise, if the fluid smells and looks fine, then the amount of fluid in the transmission is all you need to worry about. If the level falls below the “add” mark or above the “full” mark, then you have too little or too much fluid; respectively. In either case, you will need to drain out the existing fluid and replace it with new fluid.