How and Why You Should Check Your Transmission Fluid?

Transmission issues can lead to unexpected and costly repairs, or otherwise damage your vehicle and reduce the engine’s lifespan. Proper maintenance and early detection can identify problems early, and your first line of defense is learning how to check your transmission fluid.

What Is Transmission Fluid?

Image via Flickr by EthelRedThePetrolHead

A transmission converts an engine’s power into the torque and speed that a vehicle needs to rotate the wheels. Since the transmission consists of multiple components, it needs fluid to lubricate all the working parts and keep them from burning up or underperforming.

There are multiple types of transmission fluids designed for different purposes. Automatic transmissions require automatic transmission fluid. Which type of automatic transmission fluid your transmission needs depends on whether it is a continuously variable transmission, a dual-clutch transmission, a traditional transmission, or another configuration.

To further complicate matters, some manual transmissions can use fluids designed for automatic transmissions, but many use heavyweight hypoid gear oil or regular motor oil. If in doubt, refer to your vehicle’s owner’s manual to see which type of fluid your vehicle calls for.

Why Is Transmission Fluid Important?

Think of transmission fluid as a sort of coolant. Automotive engines are very sophisticated machines that generate intense heat. Without proper lubrication, that level of internal combustion can melt steel.

Transmission fluid ensures that your transmission’s working parts stay free from damage and debris. When properly lubricated, the transmission remains cool and prevents the gears from grinding against one another. Over time, the fluid collects a considerable amount of debris that would otherwise deposit on the transmission’s components, which is why the fluid needs to be changed regularly to ensure all that heat being generated is easily dissipated.

Signs of Transmission Fluid Problems

There are a few notable signs that your transmission needs a flush or new fluid. In general, you should have your transmission flushed every two years or every 30,000 miles, but defer to your owner’s manual for more accurate recommendations.

Slipping Gears

Dirty transmission fluid (or too little fluid) can create a lack of hydraulic power, causing gears to slip. You’ll notice the slippage when the car shifts gears. It will feel like the gear you’re driving in changes for no reason, and the change may even be accompanied by a high-pitched or whining sound. In some cases, the car will shake during gear shifts.

A vehicle’s safety is unpredictable when the transmission slips, so avoid driving it and have it serviced as soon as possible.

Sluggish Gear Shifts

Whether you drive an automatic or manual transmission, too much sludge can cause a sluggish response when shifting gears. This problem is particularly noticeable with manual vehicles, as changing gears can become very difficult.

Keep in mind, however, that sluggish gear shifting doesn’t always indicate an issue with the transmission. For example, a bad clutch can cause the same sort of issue. Either way, if your car hesitates before lurching into gear, it’s worth having it looked at.

Strange Sounds

When you’re behind the wheel, if you notice any unusual sounds such as grinding or whining, pull over and check the transmission fluid while the engine is still running. Vehicles tend to make these noises when the transmission fluid is contaminated or sludgy.

The fluid should appear bright red; it will turn black or brown with sludge or grime. If the fluid level seems fine but the color is off, you’ll need to schedule a transmission flush.

Vehicle Surging

A transmission that is polluted with contaminants will cause a vehicle to inexplicably surge or jump forward. In reverse, the car may even feel like it’s slipping or falling backward. Clean transmission fluid prevents this problem and ensures the gears operate smoothly.

Fluid Leaks

In some cases, transmission fuel leaks are to blame for vehicular problems. You may notice a puddle forming underneath your car when parked on pavement or in the garage. While various fluids can leak out from underneath your vehicle, transmission fluid appears slippery and red (or darker, if it’s been a while since your last transmission flush) with an oily smell.

Transmission fluid leaks typically aren’t too serious unless the car has lost a lot of fluid and its levels are low. Even so, your service center technician can address the issue before it causes additional problems.

How to Check Transmission Fluid Levels

Checking your transmission fluid isn’t as difficult as you might think, but you do need to follow a few specific steps. First, park your vehicle on a level surface, keep the engine running, and engage the parking brake. Allow the engine to warm up if it hasn’t already.

Next, locate the transmission fluid dipstick. Refer to your owner’s manual if you’re not sure where it is. Remove the dipstick, wipe it clean with a lint-free rag, and reinsert it fully just as you would when checking the oil. Remove it and hold it carefully (it may be hot) while observing the markings on the dipstick.

The fluid level on the dipstick should indicate full at the “warm” line. If it doesn’t come up to that line, you’ll need to add more transmission fluid, which you can do using a funnel and topping it off with just enough to reach that line. For optimal performance, only use the fluid specified in your vehicle’s owner’s manual.

Before adding more fluid, however, check the fluid quality. Dip your finger into the transmission fluid on the dipstick and look at the color. Rub it between your finger and thumb if necessary. The fluid should be mostly clear with a pink or red tint and it shouldn’t smell burnt. If you notice any discoloration or particles, it’s a good sign that it’s time for a flush. When you’re finished, reinsert the dipstick fully taking care not to spill any fluid on the hot engine components.

At the first sign of transmission issues, schedule a car service at Hiley Mazda of Fort Worth. Experience exceptional service and superior maintenance carried out by our factory-trained technicians. There’s nobody else who knows your Mazda better.