You should change your transmission fluid between 30,000 and 60,000 miles or from 50,000 to 100,000 miles, depending on whether it’s a manual or automatic transmission.
Gearboxes have to endure extreme conditions, and they have complicated mechanisms with many parts that must work with extreme precision. Besides, automatic transmissions also use transmission fluid to help the valve body to work properly, among other things. Transmission fluid wears out due to heat exposure, oxidation, and contamination. Proper lubrication is key to keeping your vehicle’s transmission healthy.
Manual Transmissions
Manual transmissions use transmission fluid to lubricate all their moving parts. Lubrication helps to reduce the friction of the many moving parts inside. This prevents damages and controls the transmissions’ operating temperature. Some manufacturers claim that their transmissions are sealed; hence they are maintenance-free for the vehicle’s lifetime. This is just a marketing strategy; you can be sure that no transmission oil can be in optimum shape after 10 years or more than 150,000 miles. To know how often you should change your manual transmission’s fluid, check your vehicle’s service manual, or ask your nearest dealer. The service interval of manual transmissions should be around 30,000 to 60,000 miles. Some heavy-duty vehicles or sports cars have shorter service intervals.
If you are unsure about how many miles your transmission fluid has or if it needs to be replaced, there are two things that you can do:
- Check your transmission fluid level and color. If your transmission oil looks dark and/or is contaminated with debris, it’s best to flush and change it asap.
- Listen for strange noises coming out of your transmission, check for leaks, and pay attention to your shift stick behavior while you are driving your vehicle. If you notice that you can’t shift accurately or are having a hard time shifting into some gears, have your transmission fluid changed and try again before going into further and more expensive repairs.
There are different types of transmission oils for manual transmissions. Read your vehicle’s user manual to see which kind of oil your vehicle needs. You can use a better oil than the one recommended by the manufacturer, but never use an oil with lower specs than required; it can be really harmful to your vehicle’s transmission.
Automatic Transmissions
These transmissions use the fluid for more than lubrication purposes. Automatic transmission fluid is used by the hydraulic systems to shift gears, keep the body and valves clean, keep the valves’ pressure constant, and more. Automatic transmissions have service intervals from 50,000 to 100,000 miles. Some automatic gearboxes require replacing one or more filters as well. There are two types of filters: internal and external. Replacement of internal filters usually requires removing the transmission’s oil pan to reach the filter. The transmission’s oil pan gasket should also be replaced in these services to avoid future leakages.
There are more than three types of automatic transmission fluids.
- ATF: stands for “Automatic Transmission Fluid.” It’s the most common type of automatic transmission oil. There are many types of ATF, depending on the transmission model and the manufacturer. Generally, all transmissions using a torque converter use ATF.
- DCTF: Dual Clutch Transmission Fluid is used by dual-clutch transmissions such as VW’s DSG, Audi’s S-Tronic, or BMW’s DCT.
- Multi-CVT: this transmission fluid is used by CVTs (Continuously Variable Transmission). These transmissions are known for their smoothness, and their shifting goes almost unnoticed.
Take a look at your vehicle’s service manual to check your automatic transmission’s fluid change intervals. Most manuals don’t tell whether you need to replace your transmission’s filter as well. If you are unsure about it, contact your nearest dealer or ask a trusted mechanic what parts and consumables are needed to change your transmission’s fluid properly.
Modern transmissions’ fluid level is hard to check. Most models don’t have a dipstick, and it’s almost impossible to check the fluid without losing some oil in the process. That’s why it’s advisable to keep a good record of every transmission fluid change. For example, let’s suppose you bought a used car and you are unsure about its transmission fluid level and condition; it’s always best just to change it. You can also pay attention to some of these symptoms:
- Check for transmission fluid leaks.
- Be alert for buzzing or rattling noises.
- Your transmission is skipping gears.
- You hear bumpy noises while your automatic transmission is shifting.
- You have transmission faults stored in your vehicle’s TCM (Transmission Control Module).
What color is transmission fluid?
Transmission fluid color varies depending on the transmission type.
- Manual transmission fluid looks like motor oil, and it is clear when it’s new, but it’s brownish or amber if you look closer.
- ATF transmission fluid is red, and the tone depends on the fluid’s manufacturer.
- DCTF transmission fluid is reddish, but it looks almost transparent when new.
- CVT transmission fluid looks similar to the DCTF fluid.
Some manufacturers are making their automatic transmission fluids blue. This is quite new, but it’s a fact.
What all these fluids have in common is that when they get worn out and contaminated, they look almost black. They look pretty much like worn-out engine oil.
Conclusion
Gearboxes are very expensive. That’s why it’s always best to keep your transmission fluid clean and change it if you are in doubt. Changing your transmission oil prematurely doesn’t do any harm and is far less expensive than having to repair or replace your vehicle’s transmission. Always refer to your service manual to check for your transmission’s fluid change intervals, and if you are unsure, just ask for professional help. You can use the intervals mentioned in this article as a reference. Always use the best transmission fluid you can buy and change it regularly. That will ensure that your transmission will run smoothly for a long time and will prevent annoying and expensive damages.
