How Automatic Transmissions Work

By Mister 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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Customer Reviews
This location is the best....
Brandon Callaway
This location is the best. Chris is amazing to deal with. Had a torque converter and rear diff replaced and they did it really fast. Highly recommend these guys. 5 out of 5 stars
Date: March 7, 2026
Website: Google
Got all my fluids changed...
Ahmer Zaki
Got all my fluids changed here on my Mercedes very good prices and they do an excellent job definitely coming back here and would highly recommend
Date: March 7, 2026
Website: Google
They did a great job...
Doug
They did a great job in keeping us informed of the process andfinished all the work in a timely and professional manner. Would recommend this shop to anyone needing transmission work for an honest and thorough job. I have used them exclusively for all my transmission needs for the last 15 years. 5 out of 5 stars definitely
Date: March 6, 2026
Website: Google
They did a great job...
Doug
They did a great job in keeping us informed of the process andfinished all the work in a timely and professional manner. Would recommend this shop to anyone needing transmission work for an honest and thorough job. I have used them exclusively for all my transmission needs for the last 15 years. 5 out of 5 stars definitely
Date: March 6, 2026
Website: Google
Thank you, Giorgio! An honest...
Bobh Yyz
Thank you, Giorgio! An honest operator…I stopped by his Mister Transmission as a mechanic diagnosed a slow leak under my car as transmission fluid.Regardless of being tied up, Giorgio came out front to my Jeep Wrangler, crawled under, came back up, and said looks and smells like oil.He suggested the auto service shop next unit over. We went in and our explained the situation to the operator. I’m in good hands with the service shop now.Bottom line: Giorgio’s good turn, at no cost to me, quickly helped steered me in the right direction.
Date: March 6, 2026
Website: Google
Was there earlier today and...
Breanne Ferguson
Was there earlier today and I must say one of THE BEST SERVICES I've had in a long time. A good mechanic or even someone good with PROPER diagnosis even if there isnt anything wromg are very hard to come by now a days and I feel very confident that my vehicle was is great hands today. Those working there truly care about helping their customers and easing minds that are over thinking about their vehicle. I highly recommend seeing Sanjay and his Mechanic in the back! They were awesome!Again BiG BIG thank you to Mister Transmission today!Well definatley be back again if any other issues pop up (hopefully not in the foreseeable future)!
Date: March 6, 2026
Website: Google
Towed our Rav4 from the...
H M
Towed our Rav4 from the dealer who said we needed a new transmission to Mr.Transmission Exeter RD. London. Thinking we had to get a rebuild, Sanjay and his tech found it only needed a new axle and rear coupler so $000's less and so happy to have an honest shop who did not take advantage.
Date: March 6, 2026
Website: Google
Dan was the best. Will...
Deanna
Dan was the best. Will always come back!!
Date: March 6, 2026
Website: Google
Great, fast and easy
Holden DeGroot
Great, fast and easy
Date: March 6, 2026
Website: Google
They did a great job...
Doug
They did a great job in keeping us informed of the process andfinished all the work in a timely and professional manner. Would recommend this shop to anyone needing transmission work for an honest and thorough job. I have used them exclusively for all my transmission needs for the last 15 years. 5 out of 5 stars definitely
Date: March 6, 2026
Website: Google
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