How an Automatic Transmission Works (RWD)
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- čas přidán 25. 06. 2024
- Here's how the automatic transmission works in your rear wheel drive car to send power from the engine to the wheels.
The purpose of an automatic transmission is send power from the engine to the drive wheels of a vehicle. It automatically decides and selects the gear ratio which will provide the appropriate torque or power to the wheels according to the driver's input and engine's power output.
To skip the disassembly, jump to 5:10.
The transmission's bell housing mounts to the engine's output at its flywheel, and drives the transmission oil pump and torque converter at its input shaft. Fluid pressure then activates a series of clutches that compress and hold one of three components of the planetary gear-set stationary (sun gear, ring gear or planet carrier), with the other two being inputs and outputs. In this transmission there are three planetary gear-sets nestled within each other along a single axis, since the transmission is mounted longitudinally underneath the middle of the vehicle for RWD.
Controlling all of this is a transmission computer inside the valve body, which is a network of hydraulic passages that direct the fluid based on the activation of solenoids. The transmission computer must select the appropriate gear, and slowly engage the clutches as to allow some slip for a smooth gear change by monitoring fluid pressure.
At the output shaft, the parking pawl locks the driveshaft stationary and a hall effect sensor reads the final output speed. Other notable components include thrust bearings, one way clutches, the transmission pump, numerous snap rings and pistons, temperature and pressure sensors, filter, the brake drum and band clutch and the transmission pan.
Please see this video to learn how a front wheel drive (FWD) transmission works:
• How an Automatic Trans...
The transmission in this video was a 5 speed automatic from a 2004 Infiniti G35 sedan with a VQ35DE engine.
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Get transmission fluid here:
amzn.to/303OUlq (US)
amzn.to/2O2k45r (Canada)
Transmission filters:
amzn.to/2LXPuHs (US)
amzn.to/301nmNC (Canada)
Transmission code reader:
amzn.to/302tnJK (US)
amzn.to/300JG9q (Canada)
Metric socket set:
amzn.to/301VmJz (US)
amzn.to/2NfvUK1 (Canada)
Please see this video to learn how a front wheel drive (FWD) transmission works:
czcams.com/video/LkK2XFnmfhU/video.html
Thnku sir keep uploading it gonna help me
Thank you for the free education this helps me a ton man
Hello sir, I have a problem with my automatic transmission on a mercedes w203,
It has a hard shift from 1st to 2nd gear when i press the throttle. (When i lightly press the pedal, it shifts normally like 30% of the time)
I went to a mechanic and he said that the lines of oil flow are broken and said to replace the whole valve body, and somehow I don't believe thats the issue.
I would really appreciate your advice and expertise.
Thank you in advance
You are doing a job welldon. My problem is reverse gear not engaging or moving my car Toyota hiace 2004,after loosing the transmission I found the reverse clutches worn out.replaced new ones but still the same result.please what else do I have to do to get it work
I still dont understand but great video reguardless! Thank you!
I've been a backyard mechanic for 30 years, but automatic transmissions have always seemed like some sort of strange witchcraft.
In a single breath you have delivered a 20 minute run-on sentence that completely explains all the mystery behind the automatic transmission!
If you don't already, you should consider teaching professionally!
Thank you!
That was by far and miles ahead the best auto trans tear down and explanation. I've seen pretty much all the others, even from known trans shops, but your video is by far the easiest to follow and maybe a second view is needed to further finish understanding how it works. You just have that uncanny skill to explain and comically use your families linens to aid you in your clean display of videos......pretty soon not even his grandmother is safe if we keep aiding in his addiction......
Thanks I'm glad you appreciate my work!
@@speedkar99 these "automatic transmissions" are actually more complicated than Saturn-5 rocket engines!
So now you have essentially mastered the presentation of the most complicated man-made machinery.
I wish you'd also introduce the design of the "failure points" in your videos - Realize that all these clever systems you take apart are also engineered to fail predictively... clutch friction particles plug the super fine "valve screens" !
It is a good game to help extend service life by defeating the built-in failures
Bravo 🤗
@@glasser2819 Thanks, and good suggestion!
@@speedkar99 I have one question.
Did you put your brother's bed sheet back on his? 😂
I wouldn’t even call myself a car guy, but these videos are very impressive. This guy isn’t getting the recognition he deserves.
Lmao speedkar99 @ 2:20 "stole my brother's bed sheet from him cause it's good at absorbing fluids and stuff" 🤣😂🤣
Haha that's a new one
Very useful though 😂
@@speedkar99 you said it tho lmao🤣
But the bro the sheet during middle of video
Transmission is more complicated than the combustion engine 🤪
It sure is way more complicated than ICE
Dude thats way more complicated
I agree, I know, and can wrap my mind around engines. I know how it all work. I have tried understanding automatic trans forever. People start talking in my head at some point every time reassembly explanations start. But I watch because I want to learn
Very true, I have rebuild lots of engines but never had the guts to try transmission 😂
Hope his brother has a new bed sheet.
You have an uncanny ability to explain the automatic transmission and I wish I knew a mechanic in Seattle with your level of expertise! Bravo!
In Seattle, you should dump the gasser(s) and go all electric, thereby negating the transmission altogether.
Thanks!
Come to Canada sometime...
@@fun_ghoul Everyone should go electric vehicle=build 10× more power plants to deliver all the electrical needs for those pieces of over priced garbage.
@@trendmassacre8423 Nice math, Jim-Bob. Sadly for you, 77% of energy is consumed by heavy industry. If it makes you feel better, tho, I mostly advocate for people to use public transit now, or better yet, walk. Try it, you overfed Yank...save on health care costs!
@@trendmassacre8423 wouldn't take anywhere near 10x as many power plants. It would require around 30% higher electricity production, so that's 1.3x as much. And production capacity can be expanded at many plants.
It's crazy to me that automakers have their processes so much under control that they can make all these components and still get a markup on them. The wonders of the industrial age.
Absolutely amazing. I work in a metal stamping factory now and I'm trying to imagine how each individual part is made and it's just staggering to think about. The complexity of the case casting, the valve body casting etc. The guys who designed this thing are absolute geniuses. When I see this I'm amazed cars are as cheap as they are.
I have a similar train of thought... Everytime I open something I examine it from a manufacturing perspective, and think of the scale of mass production, it's immense!
ATs are really not as complicated as they seem on first glance.. First of all we have to appreciate the fact that with relatively small design differences, all auto transmissions are pretty much constructed on the same principles, with the caveat of electronics that have compacted the design of ATs considerably, when you consider that ATs were first produced when there was no electronics, back in 1948 when the first true AT was installed on production model Oldsmobile, when there was no calculators, desktop computers or CAD software. All designed by hand on drawing boards.
So when a team of engineers design a new transmission, they are not designing it grounds up (the planetary gears, Systems of Limits and Fits, Spline housings, shafts, bearings and other machined or stamped parts are pretty much the same with variations in size. The same goes for castings. All aluminum castings are variations of the same thing. In fact CAD systems such as SolidWorks have built in elements for AT design as a standard feature.
Anyway, these videos are absolutely awesome and I do hope that one day you will invest in an actual disassembly table so you won't have to sit on the ground for all this amazing work.
Good job, man...Keep it up.
Once you have the design worked out, it’s just a matter of getting the infrastructure to build it.
That’s why the prototypes cost so much, while the production version-whatever we’re talking about-isn’t nearly as expensive.
one mystry of my life got more mysterious !
going to have some coffee
You might need a few cans of redbull for this one too haha
Yeah. It's complicated
Incredible stuff, how do people come up with this. The number of skills needed to put something like this together, the technologies, equipment, cooperation between different teams, designs, prototyping. Truly amazing.
Then when something goes wrong, people call it stupid junk and throw it out..
Thanks for showing this! I always get an urge to really completely understand everything that goes on something I take apart (like you, I reckon), but that seems impossible in something as complex as this. Imagine just trying to trace out all those channels in the hydraulic maze..
It's amazing but I think the designs was a slow evolution of something very simple. They can't just come up with this right away
Because people are created in the image of God
Still don't really understand how all the different clutches, circuits, and inputs work, but you did an excellent job describing them step by step. Thank you
Thanks. It's something you have to feel in person
I went to an auto repair school 50 yrs ago and as part of the final exam we had to take an automatic transmission apart and repair and rebuild a motor. Lucky for me my 57 chevy convertible needed both and under the tutilage of Mr. Sam I achieved a passing grade and got both done. Although it wasn't as complicated as transmissions today. It took me 6 months to learn what i watched in 20 minutes in this video! Good job.
Glad you appreciate my condensed version , it takes alot of learning for me to compress this thanks
Out of all of the videos that explain that auto transmissions have planetary gears that change the ratio, this is the first one I've found that actually explains HOW that happens. Thank you!
Welcome
Bright minds make complicated things simple and small minds make simple things complicated. You have a bright mind sir.... thank you.
Thanks
Never realized a used toothbrush can be turned into such a helpful hand on tool in automotive engineering, it provided a pinpoint precise description in every little component part within Automatic Transmission. Well done!
His brother is not going to be too happy when he goes to brush his teeth.......
Transmissions are so intimidating to work on because not only is it so many parts, but it’s so many parts and every single part has such an extremely important function lol
This guy is amazing! Automatic transmissions can be very complicated but this video does a very good job of giving a general overview of the whole shebang in a short 20 minutes. Entertaining and informative. I wish he could work on my car!
Yeah I'm gonna have to watch this a few times because holy shit that is so many moving things.
Complex and ingenious. If I had never learned about automatic transmissions and I was asked to design one I would probably take a standard transmission and use an abhorrent combination of centrifugal clutches connected to a nightmare of sprockets, chains, shafts, and rods.
It would be a mechanical abomination.
I've been struggling to wrap my mind around the automatic transmission for a while now. Probably 4-5th time I've tried watching videos, even this one. But I think this time it finally sank in. Your videos are great!
Thank you so much for skipping all the unnecessary bolt removals and whatnot, you didn't leave any time to get bored and got right into it. I've seen all the animations and whatnot. They're great for understanding the basics but they leave out the finer details. Watching the disassembly from start to finish was so much more satisfying and informative.
And the dry humor was excellent
When he got to the Planetary gear set, I lost it 😱 🤯
🙊
This video is a great testament to human ingenuity. Like others have said below, what an engineering marvel an automatic transmission is and to think there are so many varieties of them out there that have been designed, developed and produced, is mind-boggling. Also, as others have said, you are a great narrator!!
I've rebuilt a few automatic transmissions, but I learned some new knowledge from your video.
Thanks I'm glad to hear that from a pro
You have explained one of THE most technically sophisticated and wholly underappreciated modern marvels such that just about anyone can understand! Not an easy task! Except for you...the Toothbrush Wielding Wizard!
Thanks
I guess people understand me now .
Brilliant video! Interesting and informative. I now know that I will never, I repeat NEVER attempt to tamper with any transmissions on my cars ever.
This is by far most underrated channel. He has his share of humour in the videos + full of stuffs that you don't get to see every other day. Its sad that people sub to dance channels where individuals dancing like monkeys or worse and they aren't interested in these valuable informational videos.
I'm glad you appreciate my video style. Thanks
Okay... I can't believe you really got your brother's bedsheet.. am sure you had some good explanation for doing that... Just like the way you are good at explaining how the whole vehicle works.
I love this
speedkar99, are you reading during the filming?- do you practice your speech thousands of times? there is nobody on CZcams who can speak so clearly and fluently like you? that's UNREAL!
I don't make lines. I say as I go. I average 3 takes for every clip until I get it right!
@@speedkar99 yeah this vid is Emmy material. Or whatever awards. thanks
@@speedkar99 My only question is - you make the remark about how making sure the pressure is not too rough or hard on the clutch packs - is that referring to the fluid quality or how hard a person is gassing the car or both, etc.?
Looks like an IQ test to me. Love the editing, just the facts and some top notch humor ;-)
Glad you appreciate it
Wow, nice job! No awful music, good pictures, good explanation. Love the bed sheet comments!
YOO!, I was actually searching for someone who would teardown a A/T for a demonstration, Man I freaking love the fact you did all this for us, Thank you so much for the hard work, You deserve a ton of Supporters.
You are welcome. Glad you could learn something!
@@speedkar99 Actually not just learn, But really satisfying to watch such Crazy Inventions of a Human.
One of the best videos out rn on how automatic transmissions work.
this is the BEST EVER explanation of the inner workings of a automatic transmission. thanks for sharing your knowledge with me.
Wow! Mind blown! Not that I understood everything, but you sure have got a knack of explaining things in a simpler way, even if things are as complicated as this!
I'm glad my phone explaination helps!
Look how simple and sophisticated this is... you're telling me we can't travel through time yet?
Automatic transmissions are so complex by today's standards. So it puts me in awe of the engineering brains that mass produced these things 50 years ago, without the aid of modern computers and CAD systems.
Agreed! Such an amazing invention
I always wondered how automatic transmissions worked. They always seemed super complicated to understand how they work but once I saw this video it doesn’t seem as complicated as I thought. Nice video.
I know a little about car engines from helping my husband and your simplified description of each component which makes the transmission work has helped me to understand how the automatic transmission works. My VW golf TDI might be toast yet when I take it to a transmission rebuild shop, I will at least know more of what they are talking about... Thanks so much.
I have to echo others here. This is by far the best explanation I've ever seen of how an automatic transmission works. Very clear, very comprehensive, and very funny. Kudos speedkar99!
Thanks im glad you appreciate my video style
52 stars for this video. These voodoo machines can be impossible to understand if they're explained by the wrong person. You and Hiram Gutierrez (Automatic Transmission on CZcams) are two of the best. Awesome job, sir.
Thanks for the compliment
This is the first video I've found that actually explains how a transmission switches gears. Thanks.
Every other video it's always like "for second gear, the sun gear engages planet gears in set 1 and the clutch pack allows the 3rd ring gear to blah blah blah" and I was always like BUT HOW does it do that and HOW does it know?
I know there's not a bunch of servos in there operating this crap so what does?
Took forever to find out "oh its just the fluid being circulated in different spots."
The automatic transmission is a work of utter genius.
That tooth brush really helps a lot as indicator to what you are explaining. Hats off to that tooth brush. Overall, this is the best explanation you can find on youtube about automatic transmission
Thanks to the teach-brush
This video is a hell of complex, but so enjoyable to watch.
Is the video difficult or the transmission ?
As soon as I saw him holding that toothbrush I knew I would finally understand this.
Well I'm glad you did!! Thanks
Fantastic video - thank you. And while I couldn’t begin to repeat everything you said I think I get the general idea. So ingenious I can’t image how these things got designed in the first place!
It started simple and then planetary gearsets just kept getting added on!
Speedkar99, you are a national treasure, for Canada that is... Your knowledge is encyclopedic and you ability to explain complex systems is awesome. Please keep it up.
I'm glad you appreciate my work! It makes me happy to know people can benefit and learn. Thanks
I could only wish for such a supportive brother like the one you have..❤
Sure.
Not saying animated transmission videos are not good, but your video is many times better. Btw, the engineers who designed automatic transmissions are under-rated...big salute to them
I am in love with the toothbrush, this is like E=mc2 Simple equatio with complex background differential equations. Kudos bro.
You are truly a wizard including an amazing gift to explain each component with great speed yet at an understandable rate....something like the transmission you're explaining. Fine man.
Thanks. Glad it helped you understand the wizardry of automatic transmissions
Imagine cleaning all, reassembling it, add the new gaskets, putting it on the car. A smile on your face, "now that's a good work done" whispered from you. You deserve a coffee, so hard putting it all together, so you go to the coffee machine near the workbench, casually then, you notice a metal ring laying there, a metal ring that was supposed to go somewhere into the gearbox, your head become all fuzzy, then under shock you notice close to the metal ring that there is a razor cutter....as last you think "that it then, it must be done".
I always thought the person who invented the automatic transmission is a freaking genius
Just stumbled upon this vid.... probably the best tutorial that I've seen.
The big pistons in the bottom of the case are accumulators that are used to control shift feel and firmness. I prefer a good hard shift because it makes the thing respond faster and it wears the frictions less, but most people don't want to feel the shift at all :/
Yes they are.
It also controls the front band clutch to lock the drum
This transmission does not have any accumulators in the case. The servo piston in the case controls the application of the front band.
There is one small accumulator in the valvebody to control the forward engagement feel.
Shift feel is completely electronically controlled in this model.
50% of mechanical engineers who sees, might be still confused after seeing this video, how automatic gears works!
That was an incredible explanation! It will take me watching it a few times again and again for my understanding of how an automatic transmission works to set firmly into my brain, but your quick paced explanation wastes no time as it covers the bulk of what everything does in a working transmission. It is the best explanation I have found on the subject…. Great Job!!
Glad you enjoyed it!
Was looking for a detailed explanation of how the valve body works and was not disappointed. Excellent video! Thank you! I’m amazed at not only the engineering it took to create the automatic transmission, but the knowledge and understanding it takes to tear one down and explain how it all works. You are amazing!
Great job explaining. 👍🏻 I will never take my transmission for granted.
I came here as a result of searching how a transmission works. Looked at a couple of basic vids and then this one. Great video with a touch of humour. Amazing how complex the transmission has become. Subscribed.
Probably the best explanation of how the auto transmission works on the net. Simply superb. I am a professional Chemical engineer and have worked on cars all my life but understanding the automatic transmission still makes my head go in circles. For me the icing on the cake was the explanation about the transmission pump which no one else ever had done and I kept wondering where is the pump. It was important for me to know if its a positive displacement pump thus meaning you can't run it dry if you want to replace the fluid by keeping the engine running and using the tranny pump to discharge all of the approx. 6 quarts and then replace it. Replacing the oil with a dead engine only gets approx. 2 quarts out.
Your tear down seemed like a GM tranny, would love to see a ZF tear down which will be similar to AISIN of Japanese cars.
Love your review style sparkled with infrequent jokes & sarcasm.
Awesome, I'll keep that in mind thanks
czcams.com/video/7ptkLEZIn84/video.html dipstick transmission flush machine in action - it puts in 2 quarts and then takes out 2 quarts - I had this cycle 20 quarts for a 11.5 quart transmission.
Spectacular explanation of this complex and little understood component. I could never understand how the clutches were activated and released and you showed it so simply. Bravo!
"Brothers bed sheets, good for absorbing fluids and stuff" got me 😂
That was a very good demo. Better than some others I've recently watched. Thank you.
Glad it was helpful!
Love your videos, excellent for the diy mechanic or anyone who is curious! Excellent presentations and you get right to it, thank you for taking the time to teach people!
Your knowledge and presentation is truly phenomenal. Thank you for making these videos.
I think I'm gonna have to watch this about 32 times before actually getting it but what an awesome video well done
It's amazing how all these bits and pieces come together. Designing it from scratch is mind blowing. But I still prefer the old school stick shift. Much more reliable. 😆 thanks for your effort in explaining though.
It's quite intringuing for me to think how this was all designed and mass manuafactured
Great! You're a very good teacher. Wish I could work side by side with you to learn everything I could about engines and transmissions.
Excellent as usual! Amazed at the amount of electronics in the oil pan!
I was quite surprised too
This was the best all around explanation of a complicated process I have ever seen! KUDOS!
This deserves more views, he explains it so well
A big thanks for detail explanation, I'm a mechanic but never opened an automatic gearbox with someone who could explain me like you just did, I've done many oil and filter changes on 5hp, 6hp, and dsg 6 and 7 gears. Thanks once more, I have hit Like and Subscription. :)
Thanks. This is indeed different than what a mechanic does.
OUTSTANDING! Thanks so much for making this. My word, you know your craft! Even as a scientist I marvel at the fact humans can design and build these sorts of things - and it is all hidden away!
One of the first videos I didn't have to watch on 2x.
*(I actually slowed it down a bit)
Really good, clear explanation. And a little levity thrown in.
Outstanding breakdown of the transmission!👍🏾👍🏾
Thank you
Great work disembling all those pieces ....bravo🤝
legend has it he's still removing parts from that housing
I still have the housing
Jesus ****ing Christ. The amount of components is mind boggling.. the mechanical engineering that went into designing this transmission from the ground up must have been crazy.
Excellent video, your brother's cameo was hilarious lol.
Lol
Love that sheet color eh 😲
by far the best transmission illustration for me
Thanks I'm glad it helped
that was a good explanation, better than some animated versions.
Dude I thank you a lot for these videos I wouldn't know half as much as I do about cars without them
Glad you enjoyed it
Phew - this makes engine work look easy.
Exactly what I needed. Thanks, guy.
Bravo. Supreme articulation my dude!!
I love learning gearbox and love your videos ...lot of respect from algiria
Dude thank you so much I’m doing these in class right now and I was hoping you would explain these because you explain everything else so well
I'm glad I could help you understand
That was incredible. Thank you!
Thank you for your efforts...
Always wanted to start understanding auto trans.
Really appreciate it, well done.
Incredible explanation. Very knowledgeable. Thanks for Sharing.
You are welcome
Man, your amazing. thanks for the explanation.
WOW! thanks for a such a clear explanation! was so easy to follow. I always wondered how the automatic gear system in cars worked and now i know :)
Welcome
cool engineering. i like the rapid explanation
And....this is why all of my cars have manual transmissions. There's beauty in simplicity. ;)
Chris Freemesser - It's true...there IS beauty in simplicity! But there can also be beauty in complexity...such as this transmission. Sure, it's hella crazy complex engineering, but the components that make up this modern marvel can damn near be likened to art. At least IMHO. Cheers!
Great.
Meanwhile I'm going to admire this marvel of engineering
@@speedkar99 Not saying the engineering isn't impressive...it just seems like a LOT of effort and complexity to save one from having to move a simple gear selector now and again. ;)
I'd be curious (and slightly nervous) to see how this tranny compares in complexity to a 9 or 10 speed auto...
Respect from Russia !
Good lesson !
Thank you !
Thanks
Loved the humor, and the explanation was very thorough.
What humor?
The mechanical one-way clutches have the same symbol that diodes use in electronic schematics...that's kind of mind-blowing
I’m still laughing at the “freshly stolen bed sheet, cause it’s good at absorbing fluids”.
14:49 Lol
Awsome! Thank you and your family's clothing for this kind of video.
You are welcome.
Soon I'll start my own clothing donation bin 🤣