One of the more complex parts of your car is the transmission. As simple as shifting the lever into gear seems, behind the scenes, complex mechanics and software do the work for you. A transmission sends the power produced by your engine to the wheels and enables you to drive at any speed.
This is important work. Should the transmission stop or break down, your vehicle will not operate. With that complexity, how long does a transmission last?
How long does a transmission last in a car?
The average mileage lifetime on an adequately maintained transmission driven in normal conditions is more than 100,000 miles. Your mileage may vary considerably depending on the car’s type of transmission. Transmission manufacturer, make and model, driving conditions, maintenance levels and wear and tear all impact mileage.
How long does an automatic transmission last?
An automatic transmission can last 100,000 miles before needing additional care. Care and maintenance of the car are critical for the life of associated mechanical parts, including the transmission. Let’s look at some of the essential things that affect the life of a transmission.
Transmission fluid maintenance
Similar to engine oil, transmission fluid serves as a coolant for moving parts. According to AAMCO, transmission fluid lubricates the bearings and metal parts inside a car’s manual gearbox, keeping them from grinding as they move.
Automatic transmission fluid also serves as a hydraulic fluid to make internal components function as designed. The transmission fluid helps with gear lubrication, brake band friction and valve operation. If degraded fluid is not replaced, it will fail to perform these essential functions, and the transmission itself may fail soon, too.
Engine cooling system
Automatic transmissions operate best at or below 200 degrees Fahrenheit. For every 20 degrees above the limit, you risk cutting the transmission’s expected lifespan by a factor of two. For example, suppose your transmission overheats to 300 degrees. In that case, the heat will reduce the transmission’s lifespan to one-thirty-second of what is considered normal. Even with the temperature going up 40 degrees, the transmission fluid can turn to varnish and won’t properly lubricate the transmission gearing. Overheating can be caused by pulling a load that’s too heavy, low transmission fluid or an overheated engine. The transmission fluid is cooled by coolant located on or near the car’s radiator. If radiator fluid isn’t cooling properly, the heat will also affect the cooling of the transmission fluid and vice versa.
Even the most powerful trucks have limits to the weight they can pull. Hauling or towing weight more than your vehicle was designed for—whether you drive a sedan or an SUV—will bring consequences, including the strain on the transmission. Manual and automatic transmission clutches will cease to function and further wear out other components.
When changing your oil, check the radiator coolant, brake fluid and transmission fluid levels. Letting the transmission run out of fluid or operating it with a low fluid level is a guaranteed way to have a transmission break down. The fluid cools and lubricates the transmission’s internal components. When the fluid level gets low or runs out, the internal parts grind and overheat, leading to failure.
How long does a manual transmission last?
Because of the simplicity of a manual transmission, its lifespan can be more than 120,000 miles. But despite their simplicity, standard transmissions aren’t indestructible. Let’s look at some issues that affect the life of your manual transmission.
Transmission fluid maintenance
Like an automatic transmission, manual transmission fluid needs to be replaced as recommended by the manual maintenance schedule. Although a manual transmission doesn’t have hydraulic parts, its gears, bearings and shafts will shed metal deposits over time. That causes accelerated wear. The good news is that changing manual transmission fluid is as easy as changing oil. Checking the fluid level ensures the smooth operation of your transmission for the lifetime of a vehicle.
Learning the proper way to clutch and shift is vital to your transmission. Grinding gears, whether through a missed shift or worn clutch, will damage a transmission’s gear teeth. Downshifting from high RPMs will put manual transmission components under stress and damage the transmission and the clutch. Your owner’s manual will suggest recommended speeds for each gear.
By depressing a manual transmission’s clutch pedal, you disconnect the shifter from the engine so you can move from gear to gear. Releasing the clutch pedal engages a spring and allows the friction material on the clutch to engage the clutch plate so the vehicle can move. The friction material and springs wear over time. As the clutch wears, you’ll feel that the engine is revving, but the car isn’t moving or doesn’t immediately move. You may also engage the clutch but the gears won’t shift, indicating a worn clutch spring. Either one of these issues will slowly happen over time and need to be replaced—usually around 100,000 miles or more, depending on how you drive.
Signs of a bad transmission
Automatic transmissions are intricate and designed to work trouble-free for the life of your car. Proper maintenance is essential to avoid repair or replacement. Try to look out for these signs to see if you may be on the road to a transmission repair.
Check engine light
Although check engine lights come on for many drivetrain or car-related issues, they can also warn of transmission problems. Possible transmission problems could be:
- Low fluid levels
- Faulty sensors
- Control unit failure
Although you can purchase an OBD II diagnostic reader to read the check engine code, it’s best to consult with a licensed automotive technician.
If you don’t see a check engine light, that’s the first sign of a transmission nearing the end. To try and find fluid leaks, look beneath the car where you park. If your transmission is leaking fluid, you’ll see reddish-brown drops or dark spots on the ground. You can touch the dots to see the color and try to ascertain the smell. Red liquid with a sweet odor is transmission fluid. If you find something else, it’s good to try and check all of your fluid levels and take your car to a technician for a checkup.
Hesitation before shifting
If your transmission lags before shifting, your car, truck or SUV isn’t kicking into gear right away. For example, you’re at a stop sign and you press your accelerator when it’s your turn to go but your vehicle doesn’t move right away. Transmission lag can also happen between the higher gears.
Revving without moving
If you are in gear and ready to accelerate and the engine revs and you don’t move, you have a transmission problem. Your transmission is unable to engage in gear. Your clutch could need a replacing, and the same holds for an automatic. A technician should check the clutch as soon as possible.
Slipping out of gear
Your transmission should shift into gear and stay until prompted by you or the computer to shift. If your transmission is slipping out of gear, there is a problem that could further damage your transmission. The issue could be with the car’s computer and not the transmission itself, but either way the transmission will suffer.
How to improve transmission life
Except for the engine, the transmission is the most complicated piece of equipment in a car. With replacement costs averaging $1,800 to $3,400, keeping your transmission trouble-free is much less expensive. Here are some tips to help you ride easier.
Regularly monitor fluid levels
If you have an owner’s manual, it should be easy to try and check your transmission fluid.
- Grab a paper towel
- Locate the transmission fluid cap under the hood
- While your engine is running, pull out the dipstick
- Wipe off the dipstick and insert it again
- Pull it out after five seconds
If everything is good, you’ll see a clear, reddish fluid that smells sweet. If you see dark fluid that smells burnt or rotten, you may have a problem and need the fluid and filter replaced.
Service the transmission at recommended intervals
Service intervals depend on make and model. Some manufacturers recommend 30,000-mile checks and others suggest up to 100,000 miles. The owner’s manual will give the recommended maintenance schedule. As long as you follow the required service, your powertrain warranty should cover any troubles with the transmission.
Stop completely before shifting into gear
Come to a complete stop when shifting from reverse to drive. Suppose you have a habit of putting your car into park before it comes to a full stop—this behavior can lead to transmission failure over time. Don’t shift into park or reverse when the car is moving.
Use your parking brake
Most automatic transmission cars have a pin called a pawl that prevents backward movement while parked. But on an inclined surface, the weight of the vehicle could cause the pin to fail. Using the parking brake takes the pressure off the pawl.
Keep your engine tuned
Because the engine and transmission work hand in hand, an engine problem will quickly become a transmission problem. Solving everything from engine overheating issues, engine and transmission mount issues and other drivetrain problems will help keep your car running trouble-free.