AAMCO Socal

AAMCO Centers of Southern California



AAMCO Socal

AAMCO Centers of Southern California

Most Common Transmission Problems

Is your transmission causing problems? Learn about the most common transmission problems you can't afford to ignore.

AAMCO Socal  | 05/30/2019  | Transmission Advice

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Most Common Transmission Problems

Besides the engine itself, your transmission is the most important part of the car. Without the transmission, your car wouldn't be able to move at all.

The transmission is what connects the engine to the wheels, transferring power into the wheels to allow your vehicle to move. It also ensures that the engine isn't operating outside its optimum revolutions per minute range and contains a torque converter to keep the engine running when the car isn't in motion.

So without a working transmission, you've got yourself a 4,000-pound paperweight.

If you see any signs of transmission issues, you need to get your car into your local mechanic right away. Here are a few signs of transmission problems you can't afford to ignore.

1. Car Won't Engage When in Gear

When you put your car in drive, it should respond immediately. If it doesn't, it's time to take it into a shop.

There are two problems that could cause this in an automatic transmission.

The first has to do with fluid--specifically, the pressurized hydraulic fluid automatic transmissions use to change gears. You see, the automatic transmission in your car actually has several features in common with the earliest Ford Model T.

Most modern automatic transmissions still rely on the planetary gear system, in which the gear teeth are always touching. There's one large central gear orbited by a group of smaller gears.

Manual transmissions shift gears by coupling a different set of gears to the transmission's input and output shaft. Automatic transmissions use a similar basic principle,

So, every time you drive your car in a certain gear, the literal gears that are spinning in the transmission wear out. To keep the gears from wearing down, the transmission uses pressurized hydraulic fluid to protect them.

If your car is hesitating or refusing to shift gears, it could indicate that the protective properties of the hydraulic fluid have deteriorated, causing the fluid to thicken. This can be fixed with an easy fluid change.

The other option is that it could be a computer system problem. When you change gears, your car's computer activates a transmission solenoid, it activates transmission fluid into the valve body to engage the correct gear.

If the computer is malfunctioning, it may cause a delay in activating the solenoid or not activate it at all. And that means your car may not shift gear, which could get dangerous on the road.

2. Burning Smell

As a rule, burning and car engines are like matches and gasoline--mixing them is a terrible idea.

A burning smell can often be attributed to overheating transmission fluid. That's a serious issue since the transmission fluid is essential in lubricating the complex (and expensive) mechanical system under your feet.

If the transmission fluid overheats, its protective properties diminish, leaving the gears exposed to friction that will cause the parts to break down over time and the buildup of debris.

If you smell burning in your car, get it to a mechanic immediately. You don't want that burning smell to turn into a fire or a ruined engine.

3. Gears are Slipping

Your gears are what keep your transmission working. Without the gears in proper working order, your transmission cannot shift gears, transfer power to the wheels, and keep the engine within a safe rotations-per-minute range.

So instead of shifting into a higher gear or staying in the same gear, your car engine is confused as to what to do. The transmission can't send the right message to the wheels. If you're on the road, this can turn into a car crash in the blink of an eye.

In short, if your gears are slipping, it's a serious safety risk.

How do you know if your gears are slipping? If you have an automatic transmission, it will feel like you're driving in one gear and then the gear shifts for no apparent reason.

The noise or pitch of noise from the engine will change when this happens. The car may also seem to struggle like it doesn't have enough power to maintain its speed, or it can't accelerate.

Remember, the car changes gears when you change between one speed range and another in order to keep the engine within a safe rotation-per-minute range. If the gear is too low or too high for your speed, the engine cannot safely support its current power output.

4. Whining, Clunking, Humming, or Grinding

If your car is working properly, it should run as smooth as a mirror. If it isn't, you may have a transmission disaster waiting to happen.

Your car should not whine, clunk, hum, or shake when it runs--engineers designed it not to. And it definitely shouldn't be grinding. The transmission fluid is there for the express purpose of preventing the gears from grinding against each other.

Some noises, especially grinding, can be attributed to transmission fluid issues. Your transmission fluid really is the workhorse of the system--without it, the whole system falls apart with startling speed.

If you hear clunking, it's possible that a part has given out or slipped out of place.

Fighting with Transmission Problems?

If you're fighting with any of these transmission problems, don't wait to fix the problem. Get your car fixed as soon as possible.

That's where we can help! We're leading transmission experts, servicing more transmissions in a day than most dealers service in a year. We know transmissions, and we can get your car back in working order in no time.

Click here to check out any special offers, or find a service center in your area.


AAMCO has more than 60 years of experience servicing and repairing transmissions and has worked on more than 20 million vehicles. Customers rely on us for:

  • Quality workmanship
  • Superior service
  • Best warranty coverage available
  • Trustworthy, honest service

AAMCO Centers of the Southern California and surrounding areas represents trust, quality and value.

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