Transmission Basics: Understanding the Basic Parts

By Mister Transmission

Before you hand over the keys, brush up on the basics of automatic transmissions so you can understand why your transmission is acting up. Here we’ll cover the basic parts of a transmission, basic transmission problems and how to know if a rebuild is in your future.

What is a Transmission?

The transmission allows you to shift your car from gear to gear, knowing how fast you need to go and how quickly you need to get there. Remarkable stuff.

Parts of a Transmission: 101

While there are many little parts inside, your transmission is essentially made up of 4 key parts of systems:

Bell Housing: This is the cone shaped metal case that you can see when you peek underneath your car. If you have a front-wheel-drive car it’s stuck on the side of the engine under the hood. If your car is rear-wheel-drive, the transmission will be mounted underneath the car behind the engine.

Gears: Even though you’re not shifting them, an automatic transmission has gears. They are broken into main gears and planetary gears. You need all of these to be able to drive.

Fluid: Transmission fluid is very important to an automatic transmission. All of the magic happens in the fluid. Most cars come with red transmission fluid, good to know if you are looking for a leak.

Filter: All of that fluid has to be clean for your car to shift gears at the right time. To keep things fresh, your transmission has a filter to catch any gunk.

Transmission Problems: 101

If your car won’t start or doesn’t run smoothly, these problems are caused by the same faults in your transmission, so whichever your car is doing, the following applies:

Is your fluid level correct?

It’s important to check your transmission fluid at least twice a year. Not only can a low fluid level cause your car to shift poorly, it can eventually lead to transmission damage, and a costly repair. If your car seems to be losing fluid on a regular basis, you may have a leak.

Is your transmission leaking?

Checking for leaks isn’t as difficult as it may seem. The transmission is a closed system, so there are only a few places that can spring a leak. Unless it’s been changed to a non-dyed fluid, your car will have red transmission fluid. Here are a few places to check for leaks:

  • At the filler tube base.
  • At the drain hole underneath the transmission.
  • Between the transmission and the engine.
  • At the selector shaft – the rod that connects your gear shift to the transmission.
  • At the speed sensor mounting point: This will either be your cable screwing into the transmission housing or an electronic sensor bolted to the housing.
  • In the radiator: If your car has a transmission cooler, it’s possible that a leak will cause transmission fluid to leak into the radiator fluid. They don’t mix well, so you’ll see it floating around in there.

Is Your Filter Clogged?

Your transmission’s filter is vital to its performance. If you haven’t replaced your filter in a while, or ever, be sure to do this before you start talking about rebuilds or replacements.

Time for a Rebuild?

When your transmission is worn out, you’ll have to have it rebuilt. For some makes and models of car this is true a little too often. The important thing is checking any other possible causes to your problem before you have it taken apart. If you haven’t replaced your filter yet, start there as this fixes a good percentage of transmission problems. If your filter is in good condition and nothing simple is out of adjustment, it’s likely you’ll need a rebuild. The good news is that at Mister Transmission we offer a rebuild warrantee so you’ll know it will get fixed and stay fixed.

Generally, transmission problems can’t be fixed by the average do-it-yourselfer. There are just too many specialized and expensive tools and pieces of equipment needed. We recommend keeping up with your regular maintenance to keep you out of the shop as much as possible.

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Customer Reviews
Great service , friendly and...
John Neven
Great service , friendly and very knowledgeable.Excellent work
Date: July 23, 2021
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Workers are very nice and...
Ely Bolivar
Workers are very nice and explain thing clearly. Also they have an option to finance your repairs.
Date: July 22, 2021
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They assessed the problem quickly,...
Colleen H
They assessed the problem quickly, quoted a good price, provided fast service, in a no-pressure, friendly manner. I've been telling everybodyService: Transmission
Date: July 20, 2021
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I took my differentials down...
Kieran Massicotte
I took my differentials down to get rebuilt and Steve was very professional and the total was 200 bucks cheaper than the quoted price and there was a few things during the whole process that didn’t go as planned as I had brought all the bearings parts and some bearings were the wrong ones and I had brought 4.88s to put in end they would not work and before continuing with anything Steve would call and double check to let you know what needs to be done and get the ok from me first before they would continue overall amazing place Steve and the guys were awesome and the work was done perfect and the diffs have never been more smooth highly recommend.
Date: July 20, 2021
Website: Google
Excellent customer service.Service: Transmission
Eduardo Vieira
Excellent customer service.Service: Transmission
Date: July 20, 2021
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Thank you Kyle and the...
Roman Danko
Thank you Kyle and the Mr. Transmission team for very professional and friendly customer service and repair. I definitelly recommend their services.Service: Transmission
Date: July 19, 2021
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Great service from these guy...
Chris Schweitzer
Great service from these guy vary happy
Date: July 19, 2021
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Always accommodating and understanding of...
Tony LePage
Always accommodating and understanding of the needs of a customer who earns his living driving. Fast friendly and great owners and staff...great service...one of my go to's for anything mechanical.
Date: July 19, 2021
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Thank you for your very...
Todd Galagan
Thank you for your very professional,honest service kyle. l high recommend !
Date: July 16, 2021
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Outstanding service, very honest and...
Lacey Skistad
Outstanding service, very honest and helpful men work here.Service: Transmission
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