What is a Shift Kit?

Today’s customers demand a transmission which shifts smoothly, is durable, and delivers excellent fuel economy all at the same time.

To accomplish these benefits we would install what is known as an automatic transmission shift kit, which is probably one of the most misunderstood upgrades in the automotive world.

Many people know the words, but not many fully understand what a shift kit truly does or why it’s desired. In short, an automatic transmission shift kit modifies the transmission’s shift timing in order to dramatically increase shift firmness and durability of the transmission components.

This is desirable because the automobile manufacturer’s engineers sometimes allow far too much shift overlap (when the transmission is actually in two gears at once) in an effort to increase shift smoothness. It’s this overly smooth, disconnected feeling that earned early automatic transmissions the label “slush box.”

While the extended shift overlap creates a very smooth shift, it also reduces the efficiency and durability of the transmission by making the friction surfaces work overtime. The added friction also creates excessive heat, which prematurely wears out seals and clutches.

Transmission shift kits can reduce this overlap time while improving the overall shifting action. By better utilizing the energy normally turned into heat by slipping during extended overlap, shift kits allow you to instead use that inertial energy for forward motion with quicker shifts, therefore you’re also able to notice improved city fuel economy.

Most vehicle owners are willing to live with the faster shift patterns in exchange for the extended durability and added fuel economy. Plus, the fact that shift kits can be installed in a few hours without removing the transmission from the vehicle makes them a logical upgrade.

We carry a variety of shift kits for most makes and models and would be more than happy to answer any questions you have. However, due to the fact that one misplaced shift valve or spring can result in a malfunctioning or damaged transmission, it’s highly recommended that you allow the experts at Mister Transmission to perform the installation of a shift kit for you. To have a shift kit installed in your vehicle’s transmission, please contact your local Mister Transmission.

Want to know more?
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Mister Transmission Team

The Mister Transmission team consists of certified transmission specialists with decades of combined experience in diagnosing, repairing, and maintaining automatic and manual transmissions.

With over 60 years of service across Canada, our experts provide trusted, accurate, and up-to-date automotive advice to help drivers make informed decisions about their vehicles.

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Customer Reviews
Very professional and helped to...
John Nutter
Very professional and helped to resolve my issue immediately
Date: June 4, 2026
Website: Google
Regardless mine was best case...
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Professional work, friendly service, reasonable...
David Molnar
Professional work, friendly service, reasonable rates.
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Outstanding service from Chris (thanks...
C
Outstanding service from Chris (thanks also to Bill) - He gave me bad news about my car with grace, compassion, and most importantly; honesty. Chris' wealth of experience and knowledge helped me make informed maintenance decisions with confidence. My sincere and heartfelt thanks!
Date: June 4, 2026
Website: Google
I wish I could put...
Heather Hunter
I wish I could put 10/10 stars. This place is excellent and I highly recommend them. I was having issues with my vehicle lagging on hills and on start off. I believed it may have been an exhaust issue which could have been costly. Joe, the front manager, is an awesome individual. Friendly and informative. One of his workers took the vehicle for a drive and came back with a diagnosis. The air filter box had not been closed properly, affecting the car's ability to receive enough air. It was fixed free of charge. Wow!! Any other mechanic would have charged me for the correction of the box. To future customers. You will not be disappointed. Keep up the awesome customer service Mister Transmission!!!
Date: June 3, 2026
Website: Google
Had all my oils changed...
Louie Elias
Had all my oils changed in my truck. It was way overdue. Brought it back for some more maintenance. Carlos hooked me up good. My truck runs and drive like its brand new.. Thanks Carlos
Date: June 3, 2026
Website: Google
These guys are great. Timely...
Barbara Bell
These guys are great. Timely service and Darren is a wonderful front desk guy. Thanks for the great work on our vehicle.
Date: June 3, 2026
Website: Google
Repairs all done in a...
Brian B.
Repairs all done in a timely fashion. Honest and upfront. Professional and personable
Date: June 2, 2026
Website: Yelp
Had a 2006 Chevy 1500...
Antonio
Had a 2006 Chevy 1500 , the transmission toqure converter was slipping, brought my truck in for repairs ended up needing a full rebuild after teardown inspection, mark was amazing threw the hole experience showing me pictures and proof of the damages worn parts etc so I had piece at mind I was not getting overcharged or getting parts I did not need even got me a used spare bell housing to keep the cost down, sarah was also amazing with calling me back with updates and information, truck was in and out with an impressive time frame. so far I have about 300km on the transmission and it’s shifting absolutely amazing and working better then I would have imagined being rebuilt, very happy with the work performed. Will post an update after a year. Driving worry free with a very nice 60,000km 3 year warranty
Date: June 2, 2026
Website: Google
Had a 2006 Chevy 1500...
Antonio
Had a 2006 Chevy 1500 , the transmission toqure converter was slipping, brought my truck in for repairs ended up needing a full rebuild after teardown inspection, mark was amazing threw the hole experience showing me pictures and proof of the damages worn parts etc so I had piece at mind I was not getting overcharged or getting parts I did not need even got me a used spare bell housing to keep the cost down, sarah was also amazing with calling me back with updates and information, truck was in and out with an impressive time frame. so far I have about 300km on the transmission and it’s shifting absolutely amazing and working better then I would have imagined being rebuilt, very happy with the work performed. Will post an update after a year. Driving worry free with a very nice 60,000km 3 year warranty
Date: June 2, 2026
Website: Google
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