What Does a Transmission Do?
To get into what transmission fluid is and why it’s important, first we should go over what exactly a transmission does. Put simply, a transmission is responsible for delivering the power from your engine down to your wheels, while also regulating said power, so your wheels can operate at different speeds. These speeds are known as “gears.”
There are two common types of transmissions found in cars today, automatic and manual:
- Manual—Less common, typically found in older vehicles. Usually requires use of a clutch pedal in order to change gears with stick shift.
- Automatic—Standard in most new vehicles. Gear shifting happens automatically within transmission as you speed up or slow down.
What Is Transmission Fluid?
Regardless of which transmission is used, both types require transmission fluid to operate properly. Transmission fluid helps make the act of shifting gears less strenuous on your vehicle by lubricating the bearings and moving metal parts within the transmission. It also helps with other functions, like:
- Torque convertor operation
- Valve body operation
- Clutch friction operation
- Brake band friction
- Transmission cooling
Like transmissions, transmission fluid also comes in two styles, automatic and manual:
- Automatic—Used in most car regardless of transmission type; typically a thin, clear fluid with a red hue, though can also be other colors depending on manufacturer.
- Manual—Heavier and darker than automatic fluid; typically used in older manual models
Servicing Your Transmission Fluid
Transmission fluid is an important component to keeping your transmission, and your vehicle, operating at its best. For this reason, it’s recommended you have your transmission fluid flushed and replaced regularly.
This is typically done every 30,000-60,000 miles, though factors like make, model, driving style, and weather can affect this. In the meantime, it’s a good idea to familiarize yourself with the tell-tale signs that you may be low on transmission fluid.
If your transmission is working properly, you shouldn’t hear any noise while you’re driving, as it should be shifting smoothly. Not only do unusual sounds differ between brands and models but they also depend on the type of transmission. Manual transmissions often make a loud clunking or grinding noise when you shift gears, while an automatic sounds like it’s whining or humming.
Noises could indicate that the fluid level is getting low, but you most likely won’t be able to diagnose the problem yourself. It’s recommended to have the issue checked out by a certified technician promptly to prevent labor-intensive repairs.
2. Burning Smell
Any foul smell coming from your car should direct you to your nearest service center. There are several reasons that a burning smell may start to come from your car and one of those is the occurrence of overheated transmission fluid. This sign can be an indication of a low fluid level.
When a transmission is too hot, higher friction between components occurs, which inevitably causes gunk to build up and corrode the transmission. If left in this condition, the transmission will ultimately damage itself enough to become non-functional.
3. Transmission Leaks
As mentioned, the fluid within your car’s transmission housing is its only source of lubrication, and it also acts as a cleaning and conditioning agent for the surrounding transmission seals. Leaks are a common cause of transmission problems, so if you notice a red fluid underneath your vehicle, then it almost certainly is losing transmission fluid.
We suggest that you contact your authorized dealer to have the transmission inspected. The repair could be an easy swap of a failed gasket or hose. However, without service, a transmission that is leaking fluid will only continue to worsen as the fluid level drops.
4. Slipping Gears
A healthy transmission will shift between gears smoothly and there won’t be any slippage. Low fluid levels can cause gears to miss, which will result in a grinding sensation. The occasional slipped gear might seem like a small issue at first, but it’s always a good idea to have the transmission looked at when this occurs to avoid costly repairs in the future.
5. Slow Gear Engagement
Along with gear slippage, low transmission fluid levels can also cause low levels of pressure, which leads to slower engagement when shifting gears. If you notice your transmission takes a second to engage when put into drive or reverse, it could be due to low fluid levels.
6. Vehicle Accelerates Poorly
If your vehicle is slow to pick up or unresponsive when accelerating from a stop, it could be caused by an issue in your transmission. If you notice this happening, you should have your vehicle inspected and serviced at the nearest service center.
7. Check Engine or Transmission Warning Light Is On
When a check-engine light pops up on your dashboard, you should always head to the nearest service center to have it investigated. There are a number of possible reasons that this light can pop up, one of them being an issue with your transmission.