Tag Archives: Transmission Basics

School of Transmission

Your vehicle’s automatic transmission is a remarkable piece of machinery. It may be complex to understand how it functions, but a little knowledge can go a long way toward preventing a breakdown

The most complex and intricate system in your car is its automatic transmission – understanding how it works can help save you time, hassle, and money. Comprised of a series of mechanical, hydraulic, and electrical components, they are all controlled by your car’s engine control unit, aka the powertrain control module.

A short drive to a nearby store means your transmission will likely shift about 25 to 30 times. Now imagine how many trips like that you make in a year and the impact they have on your transmission.

Shift Your Thinking about Your Automatic Transmission

Automatic transmission gear changes are monitored and executed by your vehicle’s internal computer. A torque converter uses the pressure and flow of transmission fluid to not only regulate the gear changes but also to allow the engine to continue running even when at a full stop. It also makes for a smoother shifting between gears.

When fluid levels in the transmission drop, so does the pressure that controls the shifting of gears. That can cause friction and less effective cooling, in turn leading to damage and potentially expensive repairs.

Recognizing Automatic Transmission Warning Signs

Preventing a breakdown from stranding you at the roadside requires insight into the warning signs your car will send if you’re on the cusp of experiencing a transmission-related problem. These warning signs include:

  • Grinding, rattling, or whining noises when changing gears or problems shifting gears
  • A delay in movement or your car jerks or shakes as it accelerates
  • Your transmission fluid is low, or you notice it pooling beneath the engine where you park
  • If you check your transmission fluid and see it’s not a reddish colour
  • You smell a burning odour while or after you drive

If you suspect your vehicle’s automatic transmission isn’t performing properly, or if you have questions about preventative transmission maintenance, contact us. Take advantage of our free 21-point multi-check inspection and avoid the cost and aggravation associated with a failing transmission.

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Transmission Parts

Transmission parts knowledge for people researching how transmissions work.

A transmission is an impressive puzzle to most drivers, made up of many intricate connections among a multitude of transmission parts. The complexity of these parts and how they fit together is intimidating, especially if you’re facing transmission repairs and you don’t understand what’s happening or why.

While we need to trust our transmission mechanics to take care of the specifics, knowing a little bit about the transmission parts that might be malfunctioning can help to set your mind at ease during the transmission repair process.

The first step to a basic understanding of transmission parts is to understand the purpose of the transmission as a whole. Your automatic transmission is responsible for transferring the power of your engine to the drive shaft and wheels so that your car can move within its optimal range of revolutions per minute (RPM). The transmission maintains this optimal range by shifting transmission gears as you drive faster or slower.

 
The main transmission parts that need to work together are:
  •     Planetary Gear Sets
  •     Hydraulic System
  •     Torque Converter
  •     Computer
Planetary Gear Sets

Manual transmissions use a clutch to connect the engine and transmission. They require the driver to shift the transmission gears, which means actually moving the gears in a somewhat linear, sliding transfer to engage with the coordinating gears needed to maintain the proper RPM ratio. Automatic transmissions keep the transmission gears in one place, in a more circular structure. This is not unlike a small solar system, hence the name Planetary Gear Sets.

Using the combination of an outer ring gear, a central “sun” gear, and two or more smaller “planet” gears, which are all constantly meshed together, the transmission takes over the gear shifting from the driver. Much like the solar system, the sun gear is in the centre and remains stationary and the smaller planet gears engage with it and the ring gear to keep the car moving smoothly.

The ring gear is connected to the input shaft, which brings power from the engine. The planet gears exist within a casing or carrier that is connected to the output shaft which carries power to the drive train and wheels. The planet gears are also connected to a clutch pack. The sun gear is connected to a drum, which is connected to the other half of the clutch pack.

Transmission clutch packs are a series of disks, half with splines on the outside edge, and half with splines on the inside edge. These alternating disks are made to fit together to lock and turn together. They do this using hydraulic functionality.

Hydraulic System

All of the transmission parts are constantly submersed in transmission fluid. This fluid is manipulated to create pressure, which pushes the transmission clutch pack together at the right time. A complex system of tubes moves the fluid around the transmission and torque converter to create this pressure. The transmission hydraulic system has three main purposes: to help control transmission gear shifting, to lubricate the transmission parts to prevent friction damage, and to keep the transmission cool. The fluid pressure within the transmission must be maintained at all times to prevent damage.

The tubes that transfer the transmission fluid have two major external seals at the front and back. The seal at the front protects the connection with the torque converter and the rear seal contains the fluid where the transmission meets the output shaft. Seals are made of neoprene. Within the transmission exists another type of seal, called a gasket, which connects and protects two stationary transmission parts. Gaskets may be made of any of a variety of materials, such as rubber or silicone. Seals and gaskets can harden over time, which might cause leaks and a drop in transmission fluid pressure, both of which can lead to damage to the transmission.

Torque Converter

When driving a manual transmission, the driver must engage the clutch or shift into neutral when the vehicle comes to a stop, such as at a red light, or the engine will stall. The torque converter in an automatic transmission allows the engine to continue running when the vehicle is stopped yet still in gear. Torque is defined as a force that causes rotation. The torque converter uses the pressure of the transmission fluid to control the rotation of its parts. When you are stopped at that red light, one half of the torque converter is turning while the other is stationary. When you accelerate, the fluid pressure forces the other half to spin in conjunction with the first half so that vehicle moves forward.

Computer

In most cars today, a computer controls the transmission’s function allowing all vehicle systems to work together for optimum fuel economy and power. As many as 30 sensors read all of the various factors such as vehicle speed, engine temperature, engine speed, etc, that control transmission gear shifting to ensure the optimal shift points are used.

The many transmission parts in your vehicle may remain a puzzle, but understanding some of the basics can help you to have a more informed conversation with your transmission mechanics before leaving it in their capable hands.

As Gene Lewis at the Moncton Mister Transmission says,

“We’re the specialists, transmissions are all we do.”

 

If you are experiencing a problem with your vehicle’s transmission, please contact your local Mister Transmission and book an appointment for our FREE 21-Point Multi-Check Inspection.

For a more in-depth explanation, please visit our Transmission School

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What is a Drivetrain?

A drivetrain may be the least understood part of a vehicle. This is due to several factors, including the fact that the term “drivetrain” is often used interchangeably with powertrain and driveline.

The drivetrain includes the transmission, the driveshaft, the axles, and the wheels. Simply put, it works in conjunction with the engine to move the wheels. The drivetrain system is an essential component of a vehicle and the transmission is an integral part of the drivetrain.

The Drivetrain and the Transmission

The drivetrain and the transmission are actually two very different concepts. The main function of the transmission is similar to the chain on a bicycle: it keeps the engine turning in time with the wheels, regardless of what gear the vehicle is in. The drivetrain represents everything that is behind the transmission involved in propelling the vehicle. The main function of the drivetrain is basically to convey power from the vehicle’s engine, through the transmission to the drive wheels on the vehicle to control the amount of torque. “Torque” is turning or twisting force.

Parts of a Drivetrain

The drivetrain is comprised of a collection of components in a vehicle that transfer power from the transmission to the wheels/ drive it forward. These components include the driveshaft, CV joints, the differential, the axle shafts and the U-joints.

  • A driveshaft is a long tube of steel that is linked to a car’s transmission at one end and the wheels at the other. It transfers the mechanical power from the transmission to the other components of the vehicle.
  • A U-joint, or universal joint, is a flexible pivot point that transmits power allowing for varying angles of the driveshaft.
  • CV joints, or constant-velocity joints, are part of the driveshaft. These joints are designed to be able to bend in any direction while continuing to turn the drive wheels at a constant velocity.
  • The differential is where the power makes its last stop before spinning the wheels (see ‘How Differentials Work’).
  • Axle shafts are a single rotating shaft, on either side of the differential, which delivers power from the final drive assembly to the drive wheels.

Driveline, Drivetrain, Powertrain

Technicians sometimes refer to driveline, drivetrain and powertrain interchangeably when referring to the drivetrain system of an automobile. This can cause confusion, but in essence, all of these terms describe the same system within the vehicle.

The powertrain in a vehicle is composed of everything that makes the vehicle move. This includes everything from the engine to the transmission to all the parts that allow the power from the engine to get to the wheels. A vehicle’s driveline consists of all of the powertrain’s components except for the engine.

The drivetrain is the part of a motorized vehicle which connects the engine and transmission to the wheel axles.

The driveline includes everything in the chain from the engine to the drive wheels, but the drivetrain consists of everything after the transmission — all driveshafts, axles, joints, differentials and wheels.

Mister Transmission technicians are all certified drivetrain and transmission specialists who service drivetrain and transmission issues in all modern vehicles.

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A Unique Hoist Designed to Facilitate Transmission Service and Repairs

Properly accessing, inspecting, and repairing a transmission requires a specialized transmission hoist which allows our certified technicians the room and visibility they need to do a thorough job every time

When it comes to getting true value for the money you pay to have a trained technician service and possibly repair your car’s transmission, it’s important to know they have the right tools and equipment to do the job. That includes the transmission hoist they use to lift up your vehicle to inspect your transmission.

It may be a less well-known aspect of transmission repair, but our unique hoist is designed to overcome any difficulties accessing, servicing, and if necessary, removing and installing transmissions in any car, light-duty truck, or SUV.

A Transmission Hoist Is Like No Other

Unlike conventional mechanic hoists found in car repair shops and dealerships, our hoist has been specifically designed to provide the most advantageous access for transmission service and repair.

This unique hoist allows our skilled and experienced mechanics to examine a transmission thoroughly and to make any necessary repairs and adjustments easily. It also gives our technicians the room they need remove and reinstall components as required for transmission repairs, such as the flywheel or clutch assembly.

Adding Value to Your Transmission Service

While our hoists are a unique tool that allows us to do our job better than a conventional mechanic’s hoist, it is not an advantage that costs you more in your transmission service and repair needs. We regard our unique transmission hoists as an important part of the world-class customer service we strive to provide you each and every time you visit one of our locations.

In fact, these hoists contribute to our efficiency and value. Because our technicians have ample space to work, they can typically complete their high-quality repairs in mere hours whereas other, non-specialized auto shops and car dealerships may take days to complete the same task.

See the difference that a transmission hoist makes in our ability to assess and repair your transmission. Contact the Mister Transmission service centre nearest you, book a service appointment, and get Canada’s transmission experts to inspect your car’s transmission.

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Transmission Systems: Computer Diagnostics

Keeping your transmission in tip-top shape calls for computer-savvy technicians and advanced transmission scan tools

When the first semi-automatic transmissions were introduced in select vehicle models in the late 1930s, few motorists could’ve known they were witnesses to the start of an evolution in how transmissions are built. More than 70 years later, the transmissions in our vehicles today are complex machines that are an intricate blend of mechanics, hydraulics, and electronics. Inspecting, maintaining, and repairing them requires the use of sophisticated transmission diagnostic tools by a professional trained in the use of high-tech systems as well as mechanical know-how.

The Complexity of Transmission Processes

Regardless of the domestic or imported vehicle you drive its transmission system is governed by an onboard computer. When something goes awry with your transmission – or if you suspect something is wrong – repair technicians rely on high-tech diagnostic tools to determine what may be wrong with it.

The mechanical components of a transmission still exist. However, each one is managed and monitored by the onboard computer. Conceivably, that makes transmission maintenance and service more complex in nature. In fact, it’s more beneficial for both car owners and automotive technicians: modern, computer-controlled transmissions provide drivers with more control of their vehicles, and it eases repair technicians’ diagnostic and service processes.

The computer running the transmission system sends and receives information about the transmission’s performance and operation. Technicians, using digital scanning tools, decipher that information to determine what the cause is of any potential transmission problem.

Reporting Faults and Error Codes

If your vehicle’s transmission system is experiencing an issue, it will log what’s known as an error fault code in the car’s onboard computer. If there your car does have a malfunctioning transmission, the technician’s scan tool will receive that error code, which will identify there is a problem. However – and this is where traditional automotive repair smarts and experience come into play – the technician will need to make a comprehensive assessment of the transmission system to figure out what is going wrong.

The good news is, knowledge is power. Once your repair technician has identified what’s impacting your transmission, they can correct it quickly, and get you and your vehicle back on the road.

And remember: the best way you can avoid a transmission failure is by ensuring preventative maintenance is performed regularly on your vehicle by a knowledgeable professional.

If you have a question about your transmission or want to book a service appointment, contact the Mister Transmission service centre nearest to you.

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