The Straight Shift with The Car Chick

Transmission Impossible: How Your Car Really Works

• LeeAnn Shattuck, The Car Chick: Your Car Buying and Repair Expert • Season 2 • Episode 116

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Summary

In this episode of The Straight Shift, The Car Chick® delves into the often-overlooked topic of car transmissions. She explains the critical role transmissions play in vehicle performance, detailing the various types including manual, automatic, CVT, dual clutch, and electric vehicle systems. The discussion emphasizes the importance of understanding how each transmission works, their maintenance needs, and the potential issues that can arise. Listeners are equipped with knowledge to make informed decisions when buying or maintaining their vehicles, particularly regarding transmission care.

Takeaways

  • Most car buyers don't realize there are multiple types of transmissions.
  • A transmission is essential for connecting the engine to the wheels.
  • Manual transmissions offer a more connected driving experience.
  • Automatic transmissions are convenient but can be expensive to repair.
  • CVTs provide fuel efficiency but can feel different to drive.
  • Dual clutch transmissions are fast but can be jerky in traffic.
  • Electric vehicles use a single-speed reduction gear for efficiency.
  • Regular maintenance is crucial for all types of transmissions.
  • Heat is a major enemy of transmission longevity.
  • Understanding your transmission can save you from costly repairs.


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LeeAnn Shattuck (00:00)
Hey everyone and welcome back to The Straight Shift, the podcast that slices through the spin and calls out all the crap so you can be a smarter car buyer, owner and driver. Today we're tackling one of the most mysterious, least understood and most expensive parts of your car. The transmission. When most people are car shopping, they think about the engine. How many cylinders does it have? How much power? Is it a turbo? But almost nobody thinks about the transmission -

beyond does it come in a stick or an automatic. And honestly, that hardly matters anymore because there are so few manuals left, which makes me very sad. But anyway, most buyers don't even realize that there are multiple different kinds of automatic transmissions, and each has their own quirks, strengths, and unfortunately, headaches. But here's the thing. Without your transmission, you're not going anywhere. It's the matchmaker between the engine and the wheels.

But if it fails, yeah, you're definitely gonna notice, usually in the form of a tow truck and a repair bill the size of a family vacation. So today I'm gonna explain the different types of transmissions, how they work, (don't worry, in layman's terms, I promise you're not gonna need an engineering degree), which ones are the most problematic, and how to get yours to last. So let's get into it.

Before we get into the different types of transmissions, let's back up and talk about why we even need a transmission at all. Engines are picky little buggers, kind like my cats at dinnertime. The job of the engine is to make power, but they only make good power in a certain RPM range, and that's revolutions per minute. If engines spin too slowly, they stall. They spin too fast,

then they run out of breath. This is why you can't just bolt an engine directly to the wheels. You'd either stall it out at every stoplight or blow the thing up on the highway. This is where the transmission comes in. A transmission is a set of gears that keeps the engine spinning in its happy zone all the time while letting the wheels spin at whatever speed you need them to go to go the speed you're going.

Let's think of this like riding a bicycle. In this scenario, you are the engine. If you're climbing a steep hill, you pick a lower gear, right? The small sprocket up front, the big one in the back. This way you have to pedal a lot, but it feels manageable to get up that hill. If you try to trek up the hill in a higher gear, which means the larger sprocket's in the front, the smaller ones in the back.

Yeah, technically you would cover more ground with fewer pedal strokes, but it would be so much harder. You'd probably have a heart attack. Hence, you want to use the lower gear to make it easier for you as the engine to get the vehicle, the bicycle, up the hill. I remember when I was in high school, the summer before my senior year, I had this wonderful opportunity to spend several weeks in France and we were biking. We

went over there and we got these 15 speed road bikes. Now we're not talking Tour de France here, but we were there at the same time as the Tour de France and we got past like we were standing still by all those incredible professional cyclists. That was amazing. But we had a lot of hills going through the French countryside in between the different youth hostels and little places that we were staying, the villages.

And we always had to make sure we were in the right gear. I'd never had a bike that had that many gears before. Plus, we were hauling everything we owned for the trip, as well as food and water on these bikes so they had extra weight. Now, remember one day we were staying at this really cute little place in a very small village. I don't remember what it was, but everybody talked about when you went out of town, because there was only one road, there was this massive hill.

I'm like, come on, it can't be that bad. So that night after we'd had some wine at dinner, we walked to the edge of town to see this hill and holy cow, I thought San Francisco was hilly. This was ridiculous. It wasn't that long of a hill, but I swear it looked completely vertical as we were standing there looking at it. And while we were standing there, one of these little tiny French cars drove up to it, stopped,

and then turn around and went the other way. They're like, no, I'm not getting up that hill. So we had to use the lowest possible gear to haul our bikes and our butts and our bags up that hill the next morning. I'm glad it was first thing in the morning when we were fresh, but it was still a whole lot of work. This is why gear ratios matter. When you get to flat ground,

Those higher gears are great. They allow you to lay on more speed without having to pedal frantically and give yourself a heart attack like a gerbil on math. So this is why you have to have a transmission. It's basically a whole set of these bicycle gears all packaged into one box. So your car can always be in the right gear for the job, whether that's creeping along in morning traffic or

merging onto the freeway like you're being chased by a swarm of angry bees. And the transmissions don't just help you go, they can also help you to slow down. If you've ever downshifted going down a hill or even just let off the throttle in an automatic, you feel the car drag a little even though you're not touching the brakes. This is called engine braking. The resistance of the engine is helping to keep your speed in check. It can only do it so much.

Truckers call this Jake braking. And that term comes from the Jacobs Engine Brake. It was one of the first widely used compression braking systems for heavy duty diesel engines. And your car essentially does the same thing. It just won't sound nearly as cool blasting through the mountains, but same principle. Okay, now that you get the why, let's dig into the different types of transmissions and how they each

pull off this fancy gear juggling act to get you where you want to go. We are of course going to start old school. The stick shift, the manual transmission, the holy grail. Anyway, a manual transmission is very much just like riding that bicycle that we just talked about. In a car, however, you've got three main players involved. You've got the clutch, you've got the shifter, and you have you. You are responsible for shifting

gears. The car is not going to do it for you. So you press in the clutch pedal. That disconnects the engine from the transmission. Then you move your shifter into gear and then inside the gearbox there's this little collar that slides over and locks you into a different gear on the output shaft. When you let the clutch back out, the engine and the transmission reconnect and you're on your way in your new gear. And hopefully you do it

smoothly. This is the trick of learning to drive a manual transmission is to get all that timing exactly right. Otherwise, you stall. But it's so cool because it's simple, it's mechanical, and you get to decide what gear you're in. Driving purists like me love it because you feel so much more connected to the car. You understand more about how it works, what the car is doing.

My daily driver, Maggie, my little MINI, she's a six speed manual and honestly, I would not have it any other way. My dad started teaching me how to drive stick when I was seven years old, when he got his Mazda RX-7 and I have never looked back. They are also a little bit cheaper to buy if you can find one and they're usually a lot simpler to repair. They can technically last forever if you don't abuse them - like

don't ride the clutch like it's a La-z-boy foot rest. And you still have to change the oil in the clutch about every 50 to 100,000 miles, depending on the car and how well you drive it. The clutch itself will wear out. Maggie finally needs a new clutch after 145,000 miles, including track time. I've done really well getting a clutch to go that long.

That is why I'm driving my mom's old Corolla right now while I wait for a whole bunch of heavily tariffed parts to arrive from Germany. Not looking forward to disassembling Maggie to change out the clutch, but it's time. The downside to a manual transmission is that driving them in stop and go traffic is a royal pain in the butt. It's about as fun as a root canal without Novocaine. Especially those of us who are getting older and our knees just really don't want to do that anymore. This is why automatics have become so much

popular and why the manuals are dying out. Most people have never learned how to drive them, but there is nothing like driving a manual. It's real driving. Anything else is just aiming. And I am, you're not going to budge me on that opinion. Let's talk about the automatic transmissions. Cause that's probably what the majority of you are driving.

They're boring, but they are easy to drive. So how they work. Imagine two desk fans facing each other inside a big metal donut filled with fluid. One of the fans is hooked to your engine. The other is hooked to the transmission. When the engine fan spins, it throws fluid at the transmission fan, making it spin too.

It's sort of like a water fight inside a donut. That's a torque converter and that is doing the work to replace the clutch Instead of a bunch of collars, like in a manual, you have what's called a planetary gear set. So picture a little tiny solar system with a sun gear in the middle and little planet gears all around it and a ring gear around those. By locking or releasing different parts

you get different gear ratios. The beauty of this is you don't need to understand it. You don't need to know what it's doing. The computers and the hydraulics, they do all the work. So all you do is put it in drive and go. It's really easy. And when done right, they can be smooth. They're super convenient. They're great for commuting and stop and go traffic, long highway trips, and even for towing things.

Your older transmissions had, four, five, six gears. Today, it's not unusual to see eight, nine, 10 speed automatics. Those are designed to help increase fuel efficiency by giving you all these different gears, everything you could possibly need to do the job without making the engine work too hard and drink too much gas. The downside...

They're really, really expensive when they break. They build up more heat than a manual transmission. So this is why you have to take really good care of it. The fluid in the transmission is the life blood. Like the vampire said, blood is life. The fluid is life. And do not under any circumstances believe this lifetime fluid BS. There is no such thing as a lifetime fluid. It's only lifetime if you define lifetime as

until the transmission dies. So change that fluid typically every 40 to 60,000 miles. Again, depending on the car and how you drive it. If you use the car to tow or if it's a Volkswagen or an Audi, you may need to change it every 30,000 miles. And you want to keep your automatic transmission cool as much as possible. Avoid overloading the vehicle.

Try to reduce extended idling. I know that's really hard in stop and go traffic, but use proper driving habits like downshifting on the inclines to minimize that heat buildup because they do give you some lower gears. But overheating and dirty fluids are what kill most automatics. Unless it's Chrysler product like our old Dodge Grand Caravan, in which case the planetary gears could just explode like the Big Bang Theory for no reason despite proper care and maintenance.

That's again, another story. Again, keep the fluids changed. That is the key to keeping your automatic transmission working properly. All right, now let's stir the pot a little bit. The CVT, that stands for continuously variable transmission. So how that works is instead of gears, you have two cone shaped pulleys with a steel belt that runs between them.

And by moving those cones closer together or further apart, the belt rides higher or lower, which changes your gear ratios. This in theory gives you an infinite number of gear ratios instead of a fixed set like seven, eight, nine, 10. You get this infinite theoretical range. It would be like pedaling a bicycle with this magical chain that can just stretch and shrink at will, giving you the exact

perfect gear ratio for whatever you need. Sounds awesome, right? In theory, yes. They can be super fuel efficient. They can be very smooth. And they can keep your engine in that sweet spot, both for acceleration or fuel efficiency. In theory.

On the flip side, it can feel weird to drive because there are no distinct gear shifts. We're kind of used to feeling when the car shifts. Less so now because automatics are getting smoother, but at least those of us purists are used to feeling our gear shifts. The other challenge is when you floor it, the engine revs up and then it kind of sits there buzzing like a weed whacker waiting for the rest of the car to catch up. It's this infamous rubber band effect.

And it also really depends on how it is programmed. Cause yes, it is controlled by computers. Some manufacturers program to maximize fuel efficiency at the expense of umpf. That's the technical term for acceleration. I had a rental Honda Civic many, many years ago. It was like maybe at 2014, somewhere in there.  I think it was a ninth gen Civic and that poor rental car, it had a CTV transmission.

It gave you like eco mode, normal mode and sport mode. I could not find a mode that worked. That poor car was never in the right gear for what I needed it to do. It was probably not programmed for my style of driving, but I have never been so miserable in a rental car, including that PT Cruiser that I had in San Diego, which was at least fun.

Some manufacturers do it a lot better than that. Like Subaru, they tend to do a good job with theirs. They give you enough umpf, because Subaru, when you need it without sacrificing too much fuel efficiency. And that's great. But the CVT in general is just very boring. It has a little bit of a droning noise that can drive people nuts. And it's about as fun as driving a can be very fuel efficient and more and more cars are going to the CVTs.

Unfortunately, they're not always the most durable, especially the earlier ones. Nissan. Nissan CVTs tended to fail, especially in the early years due to a combination of things. Design flaws, manufacturing issues, poor maintenance, because remember that whole lifetime fluid BS? Yeah, that led to overheating problems, fluid breakdown, premature wear of the belt and pulley systems, inadequate cooling.

They'd start to shutter, then they'd lose power and you'd end up having to replace it. And it's very expensive to do so. Nissan has a reputation for being very forward thinking with their engineering. They're not afraid to try things and they have some epic failures that go along with their engineering boldness, but

their CVTs have gotten a lot better. Just beware if you're looking at buying an older Nissan that has a CVT, you're taking a big risk. So again, to take care of a CVT transmission, change the fluid. There's no such thing as a lifetime fluid. I don't care if they tell you it's a closed system. It's not designed to be changed. Bullshit. Pardon my French. Fortunately, most manufacturers now have figured out that yeah, you really do need to service the fluid.

So they have included that service in their maintenance schedules. But if you're buying a vehicle that has a CVT transmission - before you buy it, look at the owner's manual. Look at the manufacturer's maintenance schedule. Does it tell you to service the transmission? Because if it doesn't, then the dealer's probably not going to do it. And you're going to have to find a mechanic that is willing to do it and knows how to do it because the car is not going to last if you don't change that fluid.

And you have to be sure to use the right fluid. Don't cheap out and get the wrong stuff because each manufacturer has very specific requirements for the fluids that work in their specific CTV transmissions. If you feel your transmission like shuddering or slipping, it just doesn't feel right, do not ignore it. They don't get better on their own. It'll only get worse and it will cost you more to fix it.

Now for the mysterious gearhead favorite, the dual clutch transmission. Imagine two manual transmissions living together in one box and working together as a team, kind like a marriage. One handles the odd number of gears and the other handles the even number of gears, and they each have their own clutch. When you're in one gear, the computer preloads

the next gear on the other side with the other transmission, the other clutch. When it's time to shift, one clutch opens and the other one closes in a fraction of a second. It's so fast. It's like passing a baton in an Olympic relay race. Smooth, instant, wicked fast. This is why high performance cars and their drivers absolutely love them. Think Porsche 911, if it doesn't have a proper manual transmission.

The Audi R8, the Nissan GTR, some of the supercars like Ferrari and McLaren use dual clutch transmissions. It's really the best thing next to a true manual when it works. That's why McLarens are not reliable, even though they're amazing. When it's not done well, they can be very jerky at low speeds and in traffic, kind like a caffeinated teenager learning to drive stick for the first time.

And repairs are ridiculously expensive. There's this thing called the mechatronics unit. It's just a fancy name for the brain. And that's a common failing point. Hyundai, unfortunately, is notorious for their dual clutch transmissions and the issues that go along with them, including premature clutch wear and overheating and some weird programming issues. Thank goodness for that 10 year 100,000 mile powertrain warranty.

But it's been so problematic in the newest generation of the Santa Fe - the new really boxy ones that they're canning it. So for 2026, the Santa Fe's are going back to their traditional eight speed automatic that is currently in the hybrid model of the Santa Fe, which works just fine. So if you're looking between the Hyundai Santa Fe and the Santa Fe hybrid, be aware they have different transmissions right now. But as soon as the 26 models come out, they'll both have

the eight speed automatic. So this is why it matters what kind of transmission the car has when you are doing your research to buy a car because they're not all the same. Even within a specific car like the Hyundai Elantra, the N model, the more high performance model uses a dual clutch. So it's important to understand the type of transmission the car has and then research. OK, what problems has this had?

problems are one of the biggest problems. In some ways they are more difficult than engine problems because when they fail, I mean, you just got to get a new one. So yeah, definitely get one that's under warranty. Again, you want to stick to your fluid change intervals religiously. Don't creep along in traffic for hours if you can avoid it because that's what makes the clutch packs overheat, especially in the dual clutch transmissions.

Again, if it feels jerky, it feels hesitant, go directly to the dealership. Do not wait until it leaves you stranded. All right. Now let's look at electric vehicles. You don't really think about electric vehicles having a transmission because they just work so differently because they don't have an engine. They have an electric motor. So EVs don't need gears in the traditional sense that regular gas cars do.

Electric motors make full torque from zero RPMs, and they can spin up to just these ridiculous speeds like 10,000, 15,000 RPMs. That's why the acceleration in an electric vehicle can be just ridiculously fantastic. And instead of trying to juggle gears, most EVs use what's called a single speed reduction gear. It takes all that speed that the motor makes

and they gear it down just once to be safe, to send it all to the wheels. It's an awful lot of torque. So they do have to kind of taper it a little bit to send it to the wheels. Some of your high-performance EVs like the Porsche Tacan, they add a two-speed gearbox to give you better acceleration and efficiency, but most of your regular EVs that, the average person can afford. One gear

is all that's needed. It's great because it's fewer moving parts, they are incredibly smooth. Did I mention that ridiculous acceleration? And there's almost no maintenance. However, if something does fail, it's fairly spectacular. The car will lose power, come to a stop, and your wallet will spontaneously combust. So that's the downside. EVs still have fluid in that reduction gear that does need changing,

usually only every 100,000 miles, but otherwise they're fairly maintenance free. You know, at least until the battery of the motor goes caput, then you're totally screwed. But that's a whole nother issue. hope this explanation of the different types of transmissions has been helpful to you, whether you are looking to buy a car or just trying to keep the one that you have going for a long time. Cause no matter what you drive, there are a few universal truths. Thanks to the laws of physics. One is that heat

kills. Overheating cooks the fluid and fries the transmission, so do your best to keep it cool. Fluid is blood. Blood is life. Different transmissions need different fluids, but they all need fluids. Manuals, automatic, CVTs, dual clutch, they all use their own types of fluids, their own special blends, so be sure to use the fluid that is specified by the manufacturer in your owner's manual.

And pay attention. If you feel your transmission is slipping, it's whining, god forbid if it's grinding or you smell burning smells. None of these things are good. Don't ignore them and hope they'll go away. They will not. They will only get worse. So have it looked at right away. You may be getting bad news from your mechanic at that point, but it's better than it leaving you stranded in the middle of the highway. And don't

overload your vehicle more than it is capable of handling. So if you use your vehicle for towing, trying to tow more than the car's rated for. It's like asking a toddler to deadlift 200 pounds. It's not going to happen. Something's going to break. And it's not just the engine that may break. Very likely it is the transmission that will give out. So be religious about your maintenance. A $200 transmission fluid change or flush every 50,000 miles,

somewhere in there that really beats a $5,000 transmission rebuild any day of the week. So to wrap this up, manual transmission, three pedals, the only real transmission in my opinion, but fun, relatively cheap, tough, but sadly quickly going extinct. Automatics, they're everywhere. They're smooth, but they're pricey to fix and change that fluid religiously. CVTs -

very fuel efficient, but can be problematic, especially the older ones before anyone, knew to change the fluid. So again, change the fluid Dual clutch transmissions - sporty, quick, super fun, but a little more high maintenance. Not every manufacturer programs them correctly or gets them right. So be wary of those. EVs - no gears, no fuss, almost no maintenance, but super expensive if they fail.

At the end of the day, the best transmission for you to have is one that you understand, know how to take care of, and that works for your lifestyle, especially if you do a lot of driving, a lot of commuting. So next time your mechanic says, hey, you need a transmission flush, you're going to know what they're talking about and why. Just make sure that your car actually needs it and you're doing it on a schedule that makes sense for the type of driving that you do.

The more stop and go driving that you do, the more towing that you do, the more frequently that fluid needs to be changed. That's what's called the extreme schedule in your owner's manual. You may not think your driving is extreme because we think extreme like racing or deserts or freezing temperatures, but it's not. Extreme simply means more heat building up in the car without it being able to cool. And that's what happens in stop and go commuter traffic.

Thank you so much for listening to The Straight Shift. If you've got a transmission horror story, I'd love to hear it. So hit me up on my website or on social media. And if you're shopping for a car, check out my online car buying course, The No BS Guide to Buying a Car. Or if you just don't want to deal with the car buying process yourself at all, you can hit me up for a free car chat. Both of those things you can book at TheCarChick.com That way you don't accidentally buy a ticking transmission time bomb.

Until next time, folks drive safely and for the love of all that is holy, if you have a manual, don't ride the clutch. I'm out of here.