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Every time you take your car, truck, or SUV for a spin, the power from the engine is transferred to the wheels via the transmission. Also known as the gearbox, or tranny in common lingo, the transmission is a crucial drivetrain component. Without it, your engine wouldn’t even be able to start your vehicle off from a standstill.
Since your vehicle’s transmission is directly exposed to the engine’s power and torque, naturally, it gets hot as you drive along. But how hot is too hot? In this article, we’ll find out what a normal transmission temperature is for most automotive applications. Then, you can learn about how to keep your transmission at or near its normal temp if things are getting a bit toasty in there.
Types of Transmissions
Broadly speaking, there are two types of transmission: automatic and manual. It’s the age-old battle – which is better? We aren’t getting into that here, but let’s say both have merits and shortcomings. Manual transmissions use a pedal-actuated clutch and H-pattern gear shifter. Automatic transmissions come in many flavors, from traditional torque converter designs to CVTs to lightning-quick dual-clutch affairs. Some use shift levers, while others employ buttons. In some cases, automatic transmissions let you manually shift gears via the gear shifter or steering wheel-mounted shift paddles. But regardless of transmission type, they are all prone to overheating. You must bear this in mind.
The Heat Equation
In an automatic transmission, most of the heat is generated by the torque converter. This crucial component uses fluid to transfer engine power to the transmission's gears and brake bands. Under high-stress conditions, the transmission fluid can shear, causing it to overheat. As the fluid heats up, its properties can break down, leading to the formation of sticky varnish deposits on critical components, such as the transmission’s valve body. Since the valve body acts as the transmission’s "brain," these contaminants can severely impact its performance, leading to potential issues.
Manual transmissions also generate heat, primarily from clutch slippage. This occurs when the clutch is not fully engaged, often due to improper driving habits or high-load conditions. Resting your foot on the clutch pedal - a common mistake - can cause unnecessary slippage, heat buildup, and premature wear. To prevent this, always ensure your left foot is completely off the clutch pedal when it's not in use. Avoid hovering over the pedal, as even slight pressure can cause damage over time.
Why Does My Transmission Overheat?
So why does the transmission overheat? Let’s go over some of the most common reasons, and you might very well be guilty of committing at least one of them.
Staying In Drive When Stopped for Extended Periods
When driving an automatic vehicle, sitting in Drive for long periods of inactivity is a great way to overheat your transmission. This is particularly likely in thick traffic on hot days. That’s because when the transmission is in Drive, your torque converter is slipping, so to speak. It’s managing a fight between your engine trying to turn the wheels and your brakes holding them in place. It’s a constant tug-of-war battle, and your torque converter is the rope. That’s why when you lift your foot off the brake pedal, your vehicle creeps forward. So, if you’re sitting at a standstill for a long period of time, shift your transmission into Neutral or Park instead of keeping it in Drive.
Towing
High load conditions are another popular cause of transmission overheating. Most people associate this with towing at higher speeds for long periods of time. They’re not wrong. That’s why you should intensify your transmission maintenance, such as fluid changes, if you regularly tow with your vehicle.
Racing
Yes, racing can definitely overheat a stock transmission if you’ve not added adequate cooling capacity. The increased power transfer demands from your performance engine, paired with the hard driving and frequent up and down shifting can easily cause your transmission to overheat.
Hot Vs Not
What temperature does an average transmission run at? The typical range tends to be 175 to 225 degrees Fahrenheit for most vehicles. At this temperature, the fluid is nicely flowing, but not breaking down. Under periodic high-load conditions, temperatures may push towards 240 Fahrenheit. Anything higher is a recipe for disaster.
Cooling Strategies
The most effective way to maintain transmission temperatures under high loads or high-performance driving conditions is to install a transmission cooler. Some vehicles already come with this, so if you still face an overheating transmission, you might want to upgrade to something beefier.
But, there’s an even more critical step in the equation, and that is to regularly change your transmission fluid. This ensures that even if there have been random overheating events, the degraded fluid doesn’t stay circulating in your transmission for long periods of time. Your vehicle owner’s manual or service schedule will tell you the typical transmission fluid change interval. For most users, this is fine. But if you’ve upgraded your vehicle’s performance, race it regularly, or tow heavy loads, you’ll want to shorten those intervals. If you’re not sure by how much to shorten them, talk to us at JEGS – we can help.
Keep Your Vehicle Running Smoothly With JEGS
We know the importance of having a smooth drive, every time. That’s why we at JEGS have a broad array of OEM-grade and aftermarket components designed to ensure that every drive is as fuss-free as possible. We carry thousands of items from the world’s most top-quality brands. So, if you’re just bringing your vehicle back up to great mechanical condition or upgrading its performance, we’ve got what you need. Talk to our team for helpful technical information, top tips, and more.
