What is a Transmission?

Your car’s transmission is the most complicated and least understood major component in your car or truck. In today’s cars, the transmission is a combination of sophisticated hydraulics and computer-controlled electronic components.

Automatic Transmission
No one component in your car has more going on inside than your automatic transmission.

The transmission is a mechanical component designed to transmit power from a vehicle’s engine to the drive axle, which makes the wheels drive the vehicle.

By varying the gear ratio, the transmission alters the levels of power and speed to the wheels. For example, in low ranges, the transmission provides more power and less speed; in high ranges, just the opposite is true. This reduces the load on the engine, while increasing the vehicle’s speed and fuel economy.

Some vehicles use a clutch to connect and disconnect the transmission to the engine, controlled through a foot pedal next to the brake pedal. These vehicles have a manual transmission. If your car doesn’t have a clutch pedal, it has an automatic transmission.

Standard Transmission
If you have to press a clutch pedal and shift the transmission manually, your car has a manual transmission.

Automatic transmissions depend on a special fluid — called ATF — to cool and lubricate the moving parts inside. But the fluid does more than that: In fact, it’s no exaggeration to say that the fluid actually drives the vehicle. So there’s little doubt that the fluid is very important to the transmission’s operation. This is why it’s important to check the transmission fluid level and condition regularly (check your owner’s manual) and to have your transmission serviced at least every couple years.

Later model front wheel drive cars also incorporate another major component into the body of the transmission itself: the differential or final drive. These types of transmissions are known as transaxles.

Automatic Transaxle
Many cars today have the final drive incorporated in the transmission, to create a transaxle.

Front wheel drive configuration improves fuel economy and handling, and reduces manufacturing costs. But because of the additional components in the transaxle, it’s generally more expensive to repair than a transmission when it fails.

If you have any questions you can e-mail them to ATRA’s Technical Department through the Technical Services page or call 1-866-GO-4-ATRA (1-866-464-2872).

To find the ATRA Member shop near you, click the Shop Finder link.

Transmission Fluid Exchange Service: Yes it’s a Real Service

You just took your car in for its regular transmission service. You have the transmission serviced about every two years, because you’d like to avoid having to spend money on a rebuild. The service writer asks, “Would you like a complete fluid exchange service at the same time?” You smile. You know that’s a scam. If it weren’t, it’d be recommended in your owners manual. They’re just looking for a way to charge you more money, right?

Not even close. A transmission fluid exchange is more than just a real service: It’s a worthwhile addition to your regular maintenance routine. Here’s why: During the more familiar transmission service, the technician removes the pan and replaces the filter. Then he reinstalls the pan and refills the transmission.

That type of service is valuable and worthwhile, but it only replaces part of the transmission fluid. In some cases, less than half of the fluid is replaced. The rest of the old, worn out fluid remains in the transmission. That’s important, because transmission fluid does more than just lubricate the transmission parts. It also cools the transmission, and even provides the connection between the engine and the wheels.

When automatic transmission fluid is squeezed between the clutch plates in the transmission, the fluid takes on a new characteristic. It acts like little “Velcro” hooks, to help the clutches grab onto one another. That holding characteristic is critical for the transmission to operate properly.

Over time, the little “hooks” in the oil wear out, through a process known as shear. When shear occurs, the transmission will begin to slip and generate huge amounts of heat. It won’t be long before the transmission is damaged from excessive temperatures.

When you have the transmission serviced normally, it replaces only a part of the worn-out fluid. The rest is left in, which can allow the transmission to slip and wear. A fluid exchange service replaces nearly all of the fluid in the transmission, which helps the transmission clutches hold tigher. This reduces heat, and can keep the transmission working for years to come.

The best type of transmission service includes both the basic filter replacement and a fluid exchange service. The filter replacement service allows the technician to examine the material in the sump, to identify potential problems and make educated recommendations for your transmission. Then the fluid exchange replaces the worn fluid, so your transmission can have a reasonable chance to last for many years.

In fact, most technicians will readily admit that if you have your cars automatic transmission serviced every two years or so, you’ll probably never need the transmission rebuilt, as long as you own your car. That’s a worthwhile service investment by any standards!

Most ATRA Members can offer you both the basic transmission service and the fluid exchange service. And they have highly trained technicians available who can evaluate your transmission through a simple road test and by examining the sediment in the bottom of the pan.

To find the ATRA Member shop near you, click the Shopfinder link.

If you have any questions you can e-mail them to ATRA’s Technical Department through the Technical Services page or call 1-866-GO-4-ATRA (1-866-464-2872)

How Much will it Cost to Fix My Transmission?

No way to tell… at least, not yet. Not until the problem has been checked thoroughly by a qualified technician. After performing those tests, a technician will be able to tell you whether you’re dealing with a problem inside the transmission, or a problem in the vehicle systems that control transmission operation.

But then he’ll be able to give you a price, right? Well, no… not completely. If the problem is in the computer system, the technician will probably have to perform additional diagnosis to identify the specific cause of the problem. That may take a half hour, or may take a few hours, depending on the problem. Once he’s identified the specific problem, the shop would be able to give you an accurate estimate of the cost to fix your car.

If the problem is inside the transmission, the shop may be able to give you a rebuild price based on the type of transmission and the transmission repair option you choose. If your preference is a custom-rebuilt transmission they’ll need to disassemble and inspect the transmission in order to give you a firm price.

The good news is that the vast majority of transmission problems that come into the shop these days don’t actually end up needing a new transmission. The repairs may end up costing less than 25% of the price of a rebuilt transmission.

The important thing is to take your car to a qualified transmission repair shop where they can diagnose your transmission problem accurately, so you don’t end up paying for work you don’t really need. The ATRA Code of Ethics — which all ATRA members are bound by — dictates that ATRA members provide competent, quality diagnosis and repairs at an honest price.

To find the ATRA Member shop near you, click the Shop Finder link.
If you have any questions, you can e-mail ATRA’s Technical Department through the Technical Services page or call 1-866-GO-4-ATRA (1-866-464-2872).

But Why Can’t I Get My Transmission Fixed in One Day?

For years we’ve been used to transmission shops advertising “One Day Service”, and for years we’ve been expecting “One Day Service”. Then it went to “One Day Service in most cases”. Now we are told, in many cases, that it will take two, three, and sometimes more days to have our transmissions repaired. So what’s the deal?!

How long will it take?
How long will it take?

In the past, a transmission shop could keep a stock of 50 – 100 rebuilt transmissions and, with few exceptions, have a transmission that would fit any given car that would come into the shop. Today, the transmissions are so varied, it would difficult (if not impossible) to provide “One Day Service”.

Here’s an example:

The 440T4 is a 4 speed automatic used in front wheel drive General Motors cars. There are three different final drive ratios, two different manual control shafts, and eight different wiring types. That comes out to be 144 variations excluding valve body calibration differences.

To put this in a nutshell, you’ll get your car back in about three days. After all, high tech is more important than convenience…or is it?