Healthy Transmissions Matter: Here’s Everything You Need to Know About Transmission Fluid

Remember the day you drove off the lot in your new Toyota Sienna? Taking a minivan home is fun for the whole family and knowing you have a reliable vehicle that meets your busy family’s needs is a relief. Enjoying a hassle-free ownership experience begins and ends with regular Toyota Sienna service. We all know the basics: oil changes, tire rotations, and alignments are part and parcel of basic vehicle care. As you accumulate mileage, though, there are other key components you should monitor regularly. One of those components is your transmission. After all, a transmission lets you drive forward, accelerate onto the highway, and reverse into a parking spot at the mall.

The transmission is part of your vehicle’s powertrain, a system that incorporates all the pieces and parts that move the vehicle, like the engine, axles, and drivetrain. Most manufacturer warranties, including Toyota’s, offer the lengthiest coverage on the powertrain because repairs for these parts are typically the most expensive. We know that regular oil changes are essential to keep your engine running cleanly, but what maintenance is required for your transmission? Maybe you’ve heard about transmission fluid, or you’ve had service professionals mention “topping off your fluids” during a routine maintenance visit, but what exactly does transmission fluid do, and how is it maintained? Let’s go over the basics.

Sienna Transmission Basics

All 2021 Toyota Sienna minivans are equipped with an electronically-controlled continuously variable transmission (CVT). The transmission also includes a feature called sequential shift mode. Sequential shift mode allows the driver to manually shift gears via a steering column-mounted shift lever. Although most drivers let the automatic transmission work its magic, having the override is a nice feature.

How does a continuously variable transmission work? First, it’s designed to maximize fuel efficiency and provide a smooth transition across the gear range. A CVT minimizes palpable gear changes (the feeling of a mild shake or jump as the car downshifts or accelerates into a higher gear) and intuitively shifts the vehicle into an ideal gear for current road conditions. CVT transmissions, also called shiftless transmission, also deliver smoother, more rapid acceleration. The physics of how they work is complicated, but basically, a CVT has pulleys (or discs or pumps) instead of gears: one for the engine and one for the wheels. They’re connected by a flexible belt, and they work inversely (as one gets larger, the other gets smaller) to deliver an infinite number of gear ratios.

Toyota’s CVT also includes a launch gear, which is designed to feel like the first gear of a traditional automatic transmission. Launch gear is a fixed low gear that stays engaged until the vehicle reaches a certain speed, at which time the CVT takes over. Launch gear has one sole function: to increase acceleration performance. CVTs eliminate upshifting and downshifting across a set gear range, so the driver won’t feel the switch that usually accompanies moving up and down into first, second, third, etc. Instead, the vehicle is constantly operating in the gear most suited to the existing road conditions, making climbing hills easier, starting and stopping more smooth, and rapid acceleration easier to access.

Transmission Fluid 101

Transmission fluid is a viscous fluid that’s designed to lubricate all the parts inside your transmission, much like motor oil does your engine. The fluid also acts as a coolant and supports the distribution of power from the engine. You can learn more about the type of transmission fluid your vehicle needs and when it’s necessary to inspect or flush it because this can vary. It’s possible to check your transmission fluid at home via the dipstick located under the hood, but the ideal way to ensure your transmission enjoys a long and problem-free life is to bring your vehicle to an authorized Toyota service center like ours for all transmission-related issues and inspections. It’s also important to follow the manufacturer’s suggested maintenance schedule.

Healthy transmission fluid is essentially clear or a slight pinkish color. If your fluid is darker, like in a red or brown color range, it’s past time to replace it. Your transmission will naturally shed metal pieces as it ages, and those particles reside in your transmission fluid. That’s why it’s important to have your Toyota-certified technician check your fluid every time you receive routine maintenance.

You’ve probably heard the term “topping off” your fluids. When it comes to transmission fluid, there are two reasons why the level of fluid in your vehicle might drop: the first is normal wear-and-tear, but the second could potentially indicate a bigger problem. That problem is a leak, which means one or more seals aren’t doing their job, and your transmission may not be getting the lubrication it needs.

Trust the Experts With This Service

Some aspects of vehicle maintenance are easier to DIY than others. Unfortunately, transmission fluid changes aren’t one of them. The process of flushing or draining your transmission fluid is complex and has the potential to create much bigger problems if done incorrectly. The risk is greater than the small amount of money you might save, so we recommend not trying it at home on your own and instead bringing your vehicle to our service center for a transmission fluid change.

Caring for Your Transmission

Your Toyota Sienna comes with a 5-year/60,000-mile powertrain warranty that covers the transmission against defects. For the transmission, this includes all internal parts, seals, and gaskets. If you experience any unusual issues with the transmission, it’s important to schedule a service appointment at a certified Toyota dealer in case warranty-related work is necessary.

Beyond mechanical defects, maintaining your vehicle’s transmission health is up to you. Luckily, it’s easy and inexpensive to keep your transmission in excellent mechanical condition. The benefits – high levels of safety, reliability, and performance – far outweigh any potential costs or inconvenience associated with obtaining service.

Toyota recommends getting your vehicle serviced every six months or 5,000 miles, whichever comes first. As far as the transmission goes, it’s likely that these checks will only require checking transmission fluid levels and topping off the fluids if they’re low. Toyota service technicians will also inspect your transmission for signs of fluid leakage.

At 30,000 miles, Toyota recommends a more thorough inspection, including all hoses and connections, then – as your vehicle accumulates mileage – a regular inspection is suggested. Transmission fluid changes are considered at around the 65,000-mile and 100,000-mile mark. Regular transmission fluid inspections during routine maintenance visits will help determine when and if a transmission fluid flush or drain is necessary.

If you regularly drive in extreme conditions, such as off-roading or in constant stop-and-go traffic, or if you tow heavy loads, it’s especially important to have your transmission inspected regularly. Todays’ transmissions are designed to withstand a lot of wear-and-tear, but be sure to follow manufacturer-recommended towing capacity ratings. Towing a load heavier than what your vehicle is designed to handle will damage your transmission and could void the warranty.

Proper vehicle maintenance is the cornerstone of a stress-free ownership experience. When it comes to your transmission – and the rest of your powertrain components – trusting an expert for regular maintenance and repairs is essential. Your Toyota-certified technician knows how to keep your transmission running great and will always use OEM parts, not cheap aftermarket substitutes.

We Can Keep Your Transmission Running Smoothly

Car ownership comes with a lot of responsibility. Even a brand new vehicle requires regular maintenance for optimal performance and reliability, which is why we recommend thoroughly reviewing your warranty and religiously following the manufacturer’s recommended maintenance schedule. The team here at Romeoville Toyota can answer all your service and maintenance questions and will help you keep your car running in showroom condition for years of driving enjoyment. Think of routine maintenance as the automotive equivalent of a dental cleaning or an annual physical. Skipping your appointments may not seem like a big deal at the moment, but it will almost always lead to bigger problems down the line. Let us handle your routine maintenance so you can keep your Sienna running smoothly.