How does your transmission work? And how to know it's in trouble.

How does your transmission work? And how to know it's in trouble.

| By: Christian Brothers Automotive

The transmission in your car is an incredibly well designed and extraordinarily complex piece of equipment. It connects directly to your engine, contains special fluid and several metal gears and components, and operates according to different speed ratios using a lot of math and engineering. Stated simply - your transmission appropriately transmits energy from your engine to other parts of your car that rotate in order to move your car forward, backward, and into park.

So, how does your transmission work? And, how will you know when it's failing to work properly?

The Importance of Your Transmission

As we said, the transmission is crucial, because your car wouldn't be able to run without one. Let’s dive in and see what your transmission does for your car.

Shifts into gear automatically

When healthy and working properly, your car's transmission should shift gears automatically, giving you the pace and performance you need to zip through the city or head out on a road trip. If your car refuses to shift gears, it’s a sure sign that your transmission is in trouble. A malfunctioning transmission that won’t shift is often due to low fluid or wrong fluid. So, if you’re putting your car in drive and you want it to move forward, make sure you take good care of that transmission!

Changes gears smoothly

Your transmission should change gears so smoothly that you should barely even be able to notice. Accelerating to pass another car on the freeway or pulling into and backing out of a parking space should be smooth and seamless. The enjoyable movement of your car is due to a properly working transmission. If your car has grinding or shaking when you are changing gears, it’s a sure sign that your transmission is in trouble. It could be a mechanical or electrical problem or some internal component, but it is definitely not supposed to do that.

Stays in gear automatically

Your transmission will help your car remain in gear automatically. When you put a properly working transmission in drive, it stays in drive. If it’s in good working order it will never suddenly drop out of gear into neutral. If your car suddenly loses momentum and you hear the engine revving up anyway, it’s a sure sign that your transmission may be in trouble. This might be something electrical or computer related and will need professional troubleshooting.

Those are the three primary functions of your transmission, and you can probably see that it is potentially one of the most important parts of your car. Since it is that important, it’s also important to take care of potential problems as soon as they begin revealing themselves, in order to prevent major damage, complications, and expenses. How, then, can I know if my transmission is failing to work properly?

How Do I Know I Need Transmission Repair?

It’s good to know up front that transmission issues are unfortunately pretty common, more so in some makes than others. With that in mind, if your transmission starts acting up we want you to know what to look for, so you can head to the auto shop sooner than later. Here are five signs that your car's transmission needs to be serviced immediately:

Slipping Transmission

Transmissions that are slipping have several symptoms, a few of which are loss of power, high pitched whistling noises, extended high RPMs, and slow downshifts. If your transmission slips while driving, it's important to have it serviced as soon as possible to prevent damage that certainly will lead to expensive repairs.

Rough Shifting

Your vehicle shifts gears as you accelerate or decelerate. Transmissions in really bad shape won't shift gears smoothly or sometimes at all. You may also hear or feel a distinctive "clunk" when it finally does shift. Your car may even lurch or shake back and forth. If this is the case, we recommend suspending your driving and contacting a tow service to bring your car to an expert mechanic.

Delayed Movement

When you first shift your car from park into drive, you might experience a long pause before the car actually starts to pull forward. If your car won't nudge, even with you giving it some gas, your transmission needs to be inspected.

Transmission Fluid Leak

Transmissions are sealed and should never leak. If your transmission is leaking, you'll notice a bright pink or red spot where you were parked. If you suspect that your transmission fluid is leaking, visit your local auto shop. Our experienced technicians will check the manufacturing specifications because they know that overfilling can lead to bigger problems. Be hesitant to refill transmission fluid on your own, unless you really know what you’re doing.

Check Engine Light

The check engine light will illuminate for various reasons, one of them being transmission problems. In fact, many newer cars today have a transmission warning light that will show up on the dashboard if the computer senses a problem. Suppose you're experiencing any symptoms outlined in this guide and suddenly notice your check engine light or transmission light is on. In that case, it's very important to seek a professional auto technician for help – don't delay!

Find Your Local Auto Repair Shop for Peace of Mind

Our team of professional technicians at Christian Brothers Automotive are experienced with transmission problems of all kinds and the maintenance needed to stop them before they even have a chance of occurring. Don't neglect your car's transmission – find your local CBA auto shop and schedule your visit with our team! We are Driving Joy with preventive maintenance and a free courtesy inspection of the overall health of your car. Experience our Nice Difference and our industry leading customer service today.


This blog was written in March 2013, and updated in August 2023, to reflect current industry standards and best practices.

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