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Transmission Repair and Maintenance

Transmissions are complicated, extremely complex and important mechanisms. Whether you have an automatic transmission or a manual transmission (or stick-shift), it ensures that power is transferred from your engine to your wheels, via the drivetrain. If it stops functioning properly, then you cannot shift your vehicle into different gears, forward or backward, which often means you will need to be towed to the nearest automotive repair shop. And repairing a transmission can be expensive. Even more expensive is transmission replacement. However, there are some measures you can take to help prevent your transmission from braking and costing you a pretty penny. But, should you find that your transmission is in need of repairs, 12th Street Auto Care Center can schedule you in today and offer you affordable costs.

ASE and AAA Approved Transmission Repair Shop

There are no finer ASE and AAA Approved transmission repair specialists in Sioux Falls who would gladly repair your transmission. Trustworthy, friendly and hardworking people who are eager to fix your vehicle and get you safely back on the road. At 12th Street Auto, you are guaranteed quality care for you and your car, and a repaired transmission while still saving money.

Automatic Transmission or Manual Transmission?

A very good bit of information to keep in mind when maintaining your vehicle is, if you are driving with an automatic transmission or manual transmission. How can you tell? Your vehicle will either have a third pedal called the clutch pedal, or it will not. Another way you can tell is by looking at the console of your car to find the shifter stick. If, on the upper surface of the console, reads PRNDL or something similar, you are driving with an automatic transmission. If, however, on the shifter stick or around it, you see numbers and the letter R, then it’s a good chance you have a stick-shift, or manual transmission. As you read down the page, you will find the components of both transmissions, as well as learn a few ways of maintaining them.

Automatic Transmission Components

An Automatic Transmission is, perhaps, the easier and more popular transmission type that someone has the option of driving. There is less of a learning curve, and it is very enjoyable. However, it can still need repairs as much as a stick-shift, if not more, due to its complex mechanical structure. For maintaining your automatic transmission, regularly getting it serviced or annually inspected, changing out the transmission filter, flushing your transmission fluid, using the right type of transmission fluid and getting your engine’s cooling system serviced can deter a lot of damage to it.

Torque Converter

The torque converter is a type of fluid coupling, or hydraulic coupling, that is used to transmit rotating mechanical power. This rotating power generated by the engine is then transferred to a rotating driven load. But none of this would be remotely possible without the torque converter’s key characteristic: to multiply torque. Regular fluid coupling cannot multiply torque, but can match the rotational speed. Without torque, your vehicle would not be able to perform adequate work.

Signs of a failing torque converter include: strange noises, like a clunking, whirring or humming, stalling at high speeds, slipping, overheating and dirty transmission fluid.

Planetary Gear Set

The planetary gear set, also known as the epicyclic gear set, in an automatic transmission is responsible for every gear ratio that your vehicle uses. Everything in the transmission depends on the planetary gearset in order for your vehicle to move, depending also on where you want it to move. The planetary gear set produces rotational force that is then sent through the output shaft that then rotates the wheels. If your car is not moving and the wheels are not receiving power, it could be that you have a failed planetary gear set.

Signs of a failed planetary gear set include: grinding noises, especially when shifted in a certain gear, buzzing noises or a loud roaring sound.

Transmission Fluid Pump

Fluid pressure, which is pumped and pressurized by the transmission fluid pump, is heavily relied on by your transmission. Without pressurized transmission fluid, the valve body would not be able to shift your vehicle into its different, selected gears. The pump also helps to lubricate the moving parts, gears, and helps everything to run smoothly.

Signs of a failed transmission fluid pump: slipping while shifting gears, various and noticeable noises, an illuminated Check Engine Light, a burning odor or smell, as well as difficulty when shifting gears.

Valve Body

Now, the transmission valve body uses the pressurized transmission fluid to open and close valves in this labyrinth system, which in turn allows your automatic transmission to shift from one gear to the next, including drive and reverse. Valve bodies are very complex and elaborate, which means that they can fail from time to time. Noises are a usual sign that something is wrong with your car, as well as leaking transmission fluid.

Signs of a failed transmission valve body: harsh or delayed gear shifts, shifting up or down automatically at the wrong time, higher RPM’s on an up-shift, noticeably loud sounds, Check Engine Lights and slipping.

Onboard Vehicle Computer and Sensors

In more modern transmissions in newer cars, it is easy to find onboard computers that serve to regulate or control the amount of transmission fluid that flows throughout the transmission. They can also send signals between the transmission and the driver via sensors, and even the transmission repair specialist when diagnosing a problem in your transmission. However, like anything mechanical or computerized, a transmission computer system can go haywire and even send false signals to either the driver or the transmission.

Signs of a failed transmission computer system includes: a delay when shifting gears, your vehicle is stuck in neutral, rough shifting of gears, incapable of down-shifting and the continued revving of your engine when pressing on your brakes.

Automatic Transmission Fluid

As stated above, transmission fluid, when pressurized, is one of the key components in shifting your automatic transmission into different gears, either up or down. Transmission fluid also acts as a lubricant for moving mechanical parts and has cooling capabilities to ensure that the transmission does not overheat. For these purposes, it is crucial that transmission fluid is flushed and refreshed annually in order to healthily maintain your vehicle, and checked at least monthly. Contaminants, metal shavings and the aging of fluid can have negative effects on your tranmission otherwise. And always check for transmission fluid leaks. A transmission without its fluid can do serious damage to your car.

Signs of bad transmission fluid or lack of fluid: strange sounds, such as grinding, a burnt smell when checking transmission fluid levels, difficulty shifting gears or slipping, surging of the vehicle, Check Engine Light and an incapability to move when shifting out of Park.

Other Automatic Transmission Components

  • Axles: part of the drivetrain, either a front, back or both. In order to move a vehicle’s wheels, they need to spin. They are connected to a drive shaft.
  • Output Shaft: carries the rotational power out of the transmission to the wheels.
  • Transmission Oil Pan: holds the transmission fluid and is located (generally) underneath your transmission.
  • Clutch Pack: a series of clutch discs and plates housed in a hub in the transmission. They are used for the multiple gears an automatic transmission would have available.
  • Transmission Bands: metal bands wrapped around the gear train. They will tighten or loosen, depending on the engaging or disengaging of gears.

Manual Transmission Components

Generally speaking, a manual transmission is simpler by design than an automatic transmission, but still has many of its own complex and intricate issues. A manual transmission cannot handle stopping on hills or stop-and-go driving as easily as an automatic transmission. They require a learning curve and even more focus when driving, especially in heavy traffic. But they are a lot of fun, costs for purchasing and repairing are generally cheaper or lower and they require less maintenance. They also require no active cooling. Truthfully, whether you buy a vehicle with a manual transmission or an automatic transmission depends on personal preference. Although a manual transmission requires less maintenance than its counterpart, we still recommend that you bring your vehicle in for checkups regularly enough to ensure its longevity.


The clutch is the part of the transmission that engages and disengages the engine with the transmission. To disengage the engine, the clutch pedal is pressed down, which allows the transmission to shift into higher and lower gears. Releasing the clutch pedal re-engages the clutch with the engine. If your vehicle begins to malfunction or perform poorly, especially with a racing engine with little speed, the clutch might be bad.

Signs of a bad clutch include: a vibrating, pulsating or chattering clutch pedal, or a stiff one, noises when in neutral or a growling when shifting gear, and slow performance or a racing engine while moving slowly.


There are three kinds of shafts in a manual transmission: the input shaft, the output shaft and the layshaft. All three function to provide your vehicle with the power and torque it needs to move the wheels, and thus the car. The input shaft connects directly with the engine and turns at the same speed as the engine. The output shaft connects to the differential. It also relays power to the wheels of the vehicle. The layshaft, along with its gears, connects as a single unit. It meshes with the gears of the input shaft and takes part in the shifting of gears.

If the differential fails, you might feel slipping in your wheels while driving, or your transmission might not create the power it needs to move your vehicle.

Signs of a bad differential or a problem with your shafts include: loss or lack of power, slipping wheels.

Gear Selector Fork

The gear selector fork slides the gears on the layshaft. The transmission is put into a higher or lower gear as the gears are slid into position. Should it not engage or disengage properly, you might feel or experience a grinding sensation as you shift into gear. If ground too much, you will wear away the teeth that turn the gears within the transmission, and render it unusable.

Signs of a bad gear selector fork include: difficulty shifting between gears, sometimes when the car is on, sometimes when the car is off, as well as a grinding feeling or noise.


Depending on the gear selected determines how much power you put into your wheels to move your vehicle. Each gear is made to create certain ratios of gear rotation within the transmission for the purpose of power. There is also the idler gear, which allows the vehicle to go in reverse. All of this is controlled by gear stick, or shifter. Between the gears are an assortment of gear sleeves and metal discs.

How many gears your vehicle can shift into depends on the vehicle you drive. Some cars are made differently than others for the sole purpose of performance: the higher the performance or power needed, the higher number of gears. A conventional manual transmission has 5- or 6-speeds to which a driver can shift, accompanied by the ability to reverse (R). Gears will eventually wear over time, especially the teeth. A car that cannot get into gear or has difficulty shifting might have a bad gear.

Signs of bad gears include: odd sounds like grinding, whirring or thumping, an inability or difficulty to shift into different gears, or a stuck car.

Napa Service Assistant

You don’t have to be an expert to know that preventive maintenance is the best way to make sure your vehicle is running properly. Use our interactive vehicle tool to learn about the maintenance and services your NAPA AutoCare Center can provide.

Napa Interactive Maintenance Tool