What happens when the transmission slips? Sometimes you notice a slight pause as your car switches from one gear to the next. In the worst-case scenario, the car chugs into the next gear or can't access the gears at all, leaving you stuck at the side of the road. Transmission problems should not be ignored or treated lightly. They're a sign of serious problems with your vehicle that need immediate attention.
What Causes Slips?
A transmission slips when one of three things happen: the fluid is low, the torque converter malfunctioned or the clutches have worn out. When any of these things happen, the driver presses on the gas and the engine revs up, but the vehicle does not move right away. Depending on how bad the transmission is slipping, the vehicle may start moving after a small amount of slippage, or it may rev up quite high before it starts to move, if it moves at all. Keep an eye on your RPM gauge if you feel a slip; if you see the RPMs spike, it's a sign of transmission trouble.
In some cases, a transmission may lag because the engine is diverting power to the air conditioning system. Try turning the AC off if you notice slipping. If the problem goes away, you know the air conditioning is the culprit. There isn't anything you can do to fix this, short of leaving the AC turned off.
Diagnosing the Problem
If you notice slippage, check the transmission fluid immediately. The transmission needs this fluid to lubricate the gears and clutches. You could do costly and extensive damage if you continue driving with low transmission fluid. If the fluid is low and you have slippage, top off the fluid and the problem should clear up.
Make sure you change your fluid every 30,000 miles or so, according to the manufacturer's recommendations. Worn bits of metal can accumulate in the fluid over time, making it less effective. If the fluid is any color other than pink, or clear oil for standard transmissions, it's time to flush the system and replace the fluid.
If the fluid is full, the problem causing the slippage is internal. Either the clutches are worn out or the torque converter is failing. The movement of the clutches against each other wears material off the clutches. If the clutches get too thin, they do not stick together and the transmission slips.
The torque converter has fins inside. These vertical fins maintain pressure so that the torque converter can send torque from the engine to the transmission. If the fins wear out and flatten, the transmission starts to slip. You can also break the fins by racing the vehicle. The fins eventually wear out under heavy-duty use and fall flat. Replacing the torque converter will solve the problem.
If things look good mechanically and you have a newer car, sensors or computer chips that run the transmission could be causing the problem. To check the computer system, you'll need to take your car to the dealer or to a specialty transmission shop, such as Mr. Transmission. There, technicians can connect a diagnostic computer to your transmission and check the electronic components to make sure they're operating correctly.
It's Rare, but It Happens
It's extremely rare for gears or bearings to fail in cars before 200,000 miles, but it can occur. Bearings will wear out over time and may need to be replaced between 150,000 and 200,000 miles.
Gears seldom break unless you're racing the vehicle, attempt to force it into reverse at a high rate of speed or operate it with very low levels of transmission fluid. These are expensive repairs, and in most cases you'll need to replace the entire transmission to get the car running again. Avoid pushing your transmission too hard, and keep a careful eye on fluid to avoid these problems.
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Full transmission troubleshooting requires a computer to read the sensors and computer chips on newer cars, but there are still some things you can diagnose and repair yourself.
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