How to Check and Change Transmission Fluid

The Importance of Proper Transmission Maintenance

As the owner of an RV or fleet vehicle repair company in Orange County, California, I know firsthand the vital role that transmission maintenance plays in keeping your vehicles running smoothly. Your transmission is the unsung hero of your vehicle, quietly and tirelessly transferring power from the engine to the wheels, allowing you to effortlessly cruise down the highway. But like any hardworking component, it requires a little TLC to keep it in tip-top shape.

You see, your transmission fluid is the lifeblood of this critical system. It lubricates the intricate gears and components, preventing wear and tear, and ensuring a seamless flow of power. But over time, that fluid can break down, become contaminated, or simply run low, putting unnecessary strain on your transmission. And trust me, you do not want to find out the hard way what happens when your transmission starts to fail.

That’s why it’s so important to regularly check and change your transmission fluid. It’s a relatively simple task that can save you from a world of headache and heartache down the road. In this comprehensive guide, I’ll walk you through the entire process, from understanding the importance of transmission fluid to properly flushing and refilling your system. By the end, you’ll be a transmission fluid ninja, keeping your RV or fleet vehicles in tip-top shape and on the road for years to come.

Understanding Transmission Fluid

Before we dive into the nitty-gritty of checking and changing your transmission fluid, let’s take a step back and explore what this magical elixir actually does. Transmission fluid serves a few key functions:

  1. Lubrication: The primary role of transmission fluid is to lubricate all the moving parts within the transmission, reducing friction and wear. This includes the gears, bearings, and clutches that work together to transmit power from the engine to the wheels.

  2. Cooling: The transmission generates a lot of heat as it operates, and the fluid helps dissipate that heat, keeping the components from overheating and getting damaged.

  3. Hydraulic Pressure: Transmission fluid also plays a crucial role in providing the hydraulic pressure needed to engage the gears and shift smoothly between them.

  4. Cleaning and Protecting: As the fluid circulates through the transmission, it helps flush out any debris or contaminants, while also forming a protective barrier on the metal components.

Over time, however, this fluid can break down and become less effective at its job. Heat, age, and normal wear and tear can cause the fluid to lose its lubricating properties, become contaminated with debris, and ultimately, compromise the health of your transmission.

That’s why it’s so important to religiously follow the manufacturer’s recommended schedule for checking and changing your transmission fluid. Neglecting this critical maintenance task could lead to costly repairs down the line.

Checking Transmission Fluid Level

Now that we’ve covered the importance of transmission fluid, let’s dive into the actual process of checking and changing it.

The first step is to assess the current fluid level in your transmission. This is a relatively straightforward task, but it’s important to do it correctly to get an accurate reading.

Here’s how you can check your transmission fluid level:

  1. Park your vehicle on a level surface: Before you begin, make sure your RV or fleet vehicle is parked on a flat, level surface. This will ensure an accurate fluid level reading.

  2. Run the engine and shift through the gears: Start the engine and let it idle for a few minutes. Then, shift the transmission through all the gears, including reverse, to circulate the fluid.

  3. Locate the dipstick: Consult your owner’s manual to find the location of the transmission fluid dipstick. It’s usually located near the front of the engine compartment, often next to the engine oil dipstick.

  4. Pull the dipstick and wipe it clean: Carefully pull out the dipstick and use a clean rag to wipe off any fluid.

  5. Reinsert the dipstick and check the level: Fully reinsert the dipstick, then pull it out again. The fluid level should be between the “Min” and “Max” markings on the dipstick. If it’s low, you’ll need to add more fluid.

  6. Add fluid if necessary: If the fluid level is low, consult your owner’s manual to determine the correct type and amount of transmission fluid to add. Slowly pour in small amounts until the level reaches the appropriate range.

Remember, it’s important to use the exact type of transmission fluid specified by the manufacturer. Using the wrong fluid can cause serious damage to your transmission, so don’t take any shortcuts here.

Changing Transmission Fluid

Checking the fluid level is just the first step in maintaining your transmission. Over time, even with regular monitoring, the fluid will need to be changed to keep your system running at its best.

Here’s how you can properly change your transmission fluid:

  1. Gather your supplies: You’ll need a few key items to get the job done, including a drain pan, new transmission fluid, and any necessary tools like wrenches or sockets.

  2. Warm up the transmission: Start by driving your RV or fleet vehicle for a few miles to warm up the transmission. This will help the fluid flow more freely during the change.

  3. Locate the drain plug: Consult your owner’s manual to find the location of the transmission fluid drain plug. It’s usually located on the bottom of the transmission case.

  4. Drain the old fluid: Place the drain pan underneath the drain plug, then carefully loosen and remove the plug. Allow the old fluid to fully drain out before proceeding.

  5. Replace the drain plug: Once the old fluid has drained, replace the drain plug and tighten it securely.

  6. Add new fluid: Locate the transmission fluid fill plug, usually on the side of the transmission case. Slowly pour in the new fluid, checking the dipstick regularly, until the level reaches the appropriate range.

  7. Start the engine and check for leaks: Start the engine and shift through the gears a few times to circulate the new fluid. Carefully inspect the area around the drain and fill plugs for any signs of leakage.

  8. Dispose of the old fluid properly: Don’t forget to properly dispose of the old transmission fluid. Many auto parts stores and repair shops will accept used fluid for recycling.

Remember, the frequency of your transmission fluid changes will depend on the make and model of your vehicle, as well as your driving conditions. Consult your owner’s manual or the team at for the recommended service interval.

Common Transmission Fluid Issues

As you can see, properly maintaining your transmission fluid is crucial for the long-term health of your RV or fleet vehicle. But even with the best care, you may still encounter some common issues. Here are a few to watch out for:

  1. Fluid Leaks: If you notice any fluid dripping or pooling around your transmission, it could be a sign of a leak. This could be caused by a loose or damaged seal, and should be addressed promptly to prevent further damage.

  2. Discolored or Dirty Fluid: Healthy transmission fluid should be a clear, reddish-pink color. If it appears dark, muddy, or has a burnt smell, it’s time for a change.

  3. Grinding or Slipping Gears: If you feel your transmission struggling to shift smoothly, or hear unusual grinding or whining noises, it could indicate low fluid levels or a more serious internal problem.

  4. Overheating: If your transmission is running hotter than normal, it could be a sign that the fluid is not adequately lubricating and cooling the system.

Any of these issues should be addressed as soon as possible to avoid further damage and costly repairs. And remember, the team at is always here to help, whether you need a simple fluid change or a more complex transmission overhaul.


There you have it, folks – your comprehensive guide to checking and changing transmission fluid. I know it might not be the most exciting topic, but trust me, it’s one of the most important maintenance tasks you can perform on your RV or fleet vehicles.

Think about it this way – your transmission is like the unsung hero of your vehicle, quietly and tirelessly working behind the scenes to keep you cruising down the road. And just like any hardworking employee, it deserves a little TLC to keep it running at its best.

By regularly monitoring your transmission fluid and changing it when needed, you’re investing in the long-term health and performance of your vehicles. It’s a small price to pay to avoid the headache and heartache of a costly transmission repair down the line.

So, don’t be a transmission slacker – get out there and check that fluid! And if you ever need a hand, or want to learn more about best practices for maintaining your RV or fleet vehicles, be sure to reach out to the experts at We’re always happy to lend a wrench (or a witty anecdote) to keep your rides running smooth.