When Should I Get My Transmission Fluid Changed?

Manual: Most manufacturers recommend that manual transmission fluid be changed every 30,000 under IDEAL conditions. Under heavy-duty use, some manufacturers suggest changing transmission fluid every 15,000 miles. The transmission industry aftermarket has recommended that under normal driving conditions that the transmission fluid should be changed every 20,000 miles or 1 year.

Why do I have to do this?

Manual Shift Transmissions: In a manual transmission, the problem is not so much the fluid degradation, but rather fluid contamination. This contamination occurs over time as the synchronizers, bearings and gears in the transmission wear out. The resulting metal particles then float around in the lubricant.

And we all know that oil with microscopic particles of metal in it does not lubricate as well as clean oil does. So if these contaminants are not drained out, they will shorten the life of your transmission.

Automatic Transmission: Because more heat is generated in an automatic transmission, automatic transmission fluid actually degrades and breaks down with use.

In addition, like in a manual transmission, automatic transmission fluid will also become contaminated with worn bits of the transmission. If these contaminants are not drained out, they will shorten the life of your transmission.

Can I Wait? What happens if I don’t do this?

If you don’t change the transmission fluid on schedule, you’ll be lubricating your transmission with metal shavings and other contaminants. This will shorten the transmission’s life. It will cause excess heat that further breaks down the fluid and more debris. The Longer the interval between services, the sooner and higher the cost of the repair can be. In other words, changing your transmission fluid at the correct interval is a good investment.

Is there any maintenance required between intervals?

Automakers have gotten better in recent years about labeling or color-coding dipsticks. The ring on the right is red to match the automatic transmission fluid, the level of which this dipstick measures. The yellow ring is clearly marked “engine oil.”

Yes. It’s important to regularly check the transmission fluid level between service intervals. Letting your car run low on transmission fluid can cause the transmission to shift improperly — or not at all. It also can harm the internal parts of your transmission, which will not be properly lubricated.

Unfortunately, you may not hear any noises or have other clues that your transmission is low on fluid, until it’s too late. So it’s important to get it checked. Unlike engine oil, transmission oil doesn’t burn up. So if you’re low on transmission fluid, you almost certainly have a leak.