When it comes to high-performance automobiles, automatic transmission are the popular option for easy and reliable driving. In this video we will explore the working principles of this complex mechanism in a simple and logical way. We’ll use an automatic transmission developed by Allison Transmission for this purpose. Automatic transmissions work based on the planetary gear set. In order to understand this process, let’s take a look at the basic parts of planetary gear sets. Planetary gear sets have two input and one output. In automatic transmission the output rotation is drawn from the planet carrier. The two inputs are connected to the ring and sun gears. Now let’s see what happens to the output speed when we apply different speeds to the inputs. Here the ring gear is stationary and rotation is given exclusive to the sun gear. This will cause the carrier to spin as you can see here. The ring gear is also rotating. The ring and sun gears rotate at the same speed. In this case the whole mechanism moves as a single unit. The ring gear speed is increased further. Turning the sun gear in the opposite direction will result in a reverse gear. So the operation of automatic transmission is all about transmitting different rotation speeds into the ring and sun gears. The beauty of automatic transmission is that this speed variation can be transmitted simply by engaging few clutch packs. In the coming sessions we well see how this is achieved in Allison. In an automatic transmission there is no direct connection between the input and the output shafts, rather there is an intermediate shaft between the two. In addition to clutch packs are used for transmitting power. Pressing the clutch packs together will lock the hub to the case. This is the simplest form of automatic transmission. With this in mind, let’s see how 1st gear works. If 1st clutch pack is applied the input shaft will connect to the intermediate shaft. On the other hand, if 2nd clutch pack is applied, the ring gear will connect to the case which will make the gear become stationary. In order to achieve 1st gear just apply both the clutch packs together. You can note that the input shaft will turn the sun gear. Since the ring gear is stationary the output shaft will rotate as shown with almost one third of the input speed. To achieve additional gear ratios at another planetary gear set. It is clear that apply C1 will always rotate the both of sun gears at the input shaft speed. If we apply C4 as well the planet carrier of the 2nd set will turn. But here is the tricky part: this planet carrier is permanently linked to the ring gear of the 1st set. So, when C1 and C4 are applied together, the ring gear of the output set will turn. Thus, at the output set the situation is similar to that at 1st gear except that here the ring gear will rotate as well. This means that the speed of the output planet carrier will increase. This is 2nd gear of the transmission. The planet carrier is also fitted with a hollow shaft. The shaft can be directly connected to the input shaft with the help of a rotating clutch module. Take a moment to observe and understand this arrangement – the rest of the process will be easy. With this setup we can achieve 4th gear with a direct drive. We know: in order to get a direct drive the ring and sun gears of the output set should rotate at the speed of input shaft. If we apply C1 and C2, this is what happens: The sun and ring gears will be directly connected to the input shaft. In order to achieve 6th gear just remove C1 and apply C4. Here at 2nd set the input rotation is given to the carrier and the ring gear is stationary. This combination gives a very high rotational speed to the sun gear. Thus, we can achieve a high over drive ratio at the output. 3rd planetary gear set is required to get the remaining gear ratios. The sun gear of this set is always connected to the input shaft as shown here. And here again the output of the set is connected to the input of the adjacent set. This means that applying C3 will always turn the ring gear of 2nd set. For the remaining gear ratios C3 is always applied. For 3rd gear just apply C1 as well. For 5th gear remove C1 and apply C2. In order to go in reverse apply the ring gear clutch C5 as well. Since the planet gear of 2nd set cannot revolve, they will spin as shown here. This will eventually lead to the reverse rotation of the sun gear. Consequently, the final output will be a rotation in the opposite direction. A transmission control unit will decide when to apply which clutch pack. Unlike manual transmissions a torque converter is needed in the automatic transmissions. When the transmission is in gear and we apply the brakes we have to isolate the rotation of the engine from the transmission. With a fluid coupling the torque converter will help accomplish this. A 2D animation will also give you a good idea of the automatic transmission system. Thank you! Subtitles are written by @IEEE_English

Automatic Transmission, How it works ?
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100 thoughts on “Automatic Transmission, How it works ?

  • July 4, 2019 at 1:20 pm
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    I finally understand now
    The sun and ring gears is fvck.

    Reply
  • July 6, 2019 at 4:00 pm
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    #ReverseMechanism
    #RevolveJet

    Reply
  • July 8, 2019 at 4:35 am
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    Worse explaition

    Reply
  • July 8, 2019 at 5:41 pm
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    This is so fascinating. The minds behind this design are no short of brilliant ๐Ÿคฏ

    Reply
  • July 9, 2019 at 12:10 am
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    I was lost after c1

    Reply
  • July 11, 2019 at 4:19 am
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    Some say not to switch from Drive to Neutral while waiting behind a red light. Is this true? Won't transmission be damaged if kept in Drive but not moving? Thanks

    Reply
  • July 11, 2019 at 4:59 pm
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    he never answer the main question
    How speed increment transfer gear from 1 to 2 or 3 ???????

    Reply
  • July 13, 2019 at 7:03 am
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    I can rebuild engines, manual trannys and differentials but I gave up on auto trannys. My friend does a great job on these and understands them well.

    Reply
  • July 13, 2019 at 10:48 am
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    i came to see comments ofter 2nd gear….. lol…

    Reply
  • July 14, 2019 at 6:35 am
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    Even as a mechanic, I don't even understand this completely. Why can't we just stay with manuals?

    Reply
  • July 14, 2019 at 4:16 pm
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    Whenever I become happy thinking about a planetary gear set and how it operates, another planetary gear set is added to make me unhappy about this endless process.

    Reply
  • July 15, 2019 at 9:59 pm
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    that does not tell how it works. it just tells about gears but nothing about atf and what role it plays in all this. it does not explain fluid drive one bit and that is why i clicked on the video in the first place.

    Reply
  • July 17, 2019 at 3:02 am
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    ๐Ÿ‘๐Ÿ‘๐Ÿ‘๐Ÿ‘

    Reply
  • July 20, 2019 at 2:14 am
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    Excellent video information Automatic Dirve Gear box Working education More Really nice, Engineering Student for Best information YouTube video Link, Nice

    Reply
  • July 20, 2019 at 3:22 am
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    it's 3am in the morning, and I have exam tomorrow, and not even a quarter of exam materials I have even reviewed… yet I am watching a transmission how-to video, and my Major is not even engineering….

    Reply
  • July 20, 2019 at 4:07 am
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    Manual transmission videos are easy to understand, everytime I watch an automatic transmission video I fall asleep for 4 hours.

    Reply
  • July 20, 2019 at 7:34 am
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    This must be a joke from Allison

    Reply
  • July 20, 2019 at 8:43 pm
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    Who needs allison 6 speed?

    We need mercedes 9 speed

    Reply
  • July 21, 2019 at 6:30 pm
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    The voiceover you hired is shit.

    Reply
  • July 24, 2019 at 8:12 pm
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    somebody kill me..

    Reply
  • July 26, 2019 at 1:51 pm
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    I couldnt understand the manual transmision and clutch, why am i here?

    Reply
  • July 26, 2019 at 3:14 pm
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    in an automatic transmission how can there be 1st 2nd … gears

    Reply
  • July 27, 2019 at 12:52 am
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    You know itโ€™s bad when Iโ€™m reading the comments as the video plays

    Reply
  • July 29, 2019 at 3:15 pm
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    My dad 03 Toyota Highlander have a 4 speed automatic … still reliable after Nearly 200k mile

    Reply
  • August 3, 2019 at 12:08 pm
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    Am l fool?

    Reply
  • August 7, 2019 at 5:29 am
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    Solidworks simulation
    https://youtu.be/4EIH1J3IAqc

    Reply
  • August 7, 2019 at 1:13 pm
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    ๋ณ€์†์˜ค์ผ์€ ์–ด๋””๊ฐ”๋‚˜?

    Reply
  • August 10, 2019 at 1:46 am
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    Can u didnt

    Reply
  • August 13, 2019 at 7:07 pm
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    This makes complete sense. Said nobody.

    Reply
  • August 14, 2019 at 12:08 pm
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    My brain has exploded I still don't get it

    Reply
  • August 18, 2019 at 6:02 pm
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    Yeah I get it, but how does it change gear when the engine reaches a certain rpm? Are the clutches electronically controlled? Or is there some mechanical frictional black magic thats happening in the gearbox that just activates the clutch at an exact rpm?

    Reply
  • August 19, 2019 at 10:30 am
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    I wonder how many people are getting lost after the first 3 mins…

    Reply
  • August 21, 2019 at 8:43 pm
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    I think the guy who made this video should be hanged for making me feel dumb!

    Reply
  • August 23, 2019 at 12:34 am
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    0:04 I didnโ€™t know they had 2HP cars

    This small engine made me uncomfortable

    Reply
  • August 23, 2019 at 12:38 am
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    After watching this video, I feel "shafted."

    Reply
  • August 23, 2019 at 12:39 am
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    Is that English or Swahili?

    Reply
  • August 24, 2019 at 4:59 am
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    Thank you so much

    Reply
  • August 25, 2019 at 4:36 am
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    Awesome video! So well explained! I had a so/so understanding of automatic gearboxes but after watching this, it has really helped fill in the gaps in my knowledge. ๐Ÿ‘๐Ÿ‘

    Reply
  • August 26, 2019 at 9:21 am
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    This video has confirmed that I am stupid.

    Reply
  • August 26, 2019 at 5:29 pm
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    It's a Ghost ๐Ÿ˜ฑ

    Reply
  • August 28, 2019 at 8:02 am
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    Simplified as much as possible:
    Clutch packs are what engage the planetary sets.
    Different combinations of planetary sets equal different gears.
    So different combinations of engaged clutch packs mean different combinations of different planetary gear sets which mean different drive gears.

    For instance:
    Engage clutch pack 1, that will engage planetary 1 and in turn, gear 1.

    Engage clutch pack 2 and 4, that will engage 2 planetaries that will result in gear 2 or 3 or whatever gear that combination corresponds to.

    Reply
  • August 28, 2019 at 6:10 pm
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    And this was the simple version??

    Reply
  • August 28, 2019 at 7:12 pm
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    And the rest will be easy ! hahaaahaa

    Reply
  • August 29, 2019 at 7:57 am
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    Anyone else felling stupid?

    Reply
  • August 30, 2019 at 11:41 pm
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    It's pathetic there are people who can't understand this after such a detailed explanation

    Reply
  • August 31, 2019 at 3:50 pm
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    You lost me at how-automatic transmission works ๐Ÿ˜ซ

    Reply
  • September 1, 2019 at 8:54 am
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    No. It's frigging magic.

    Reply
  • September 1, 2019 at 3:30 pm
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    Uhhhhhh, yeah. I remember reading that 2 things have been developed by engineers that are real marvels. One is the color television picture tube and the other is the automatic transmission. After viewing this, I can vouch for the transmission.

    Reply
  • September 4, 2019 at 6:31 am
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    and im lost

    Reply
  • September 4, 2019 at 8:50 pm
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    Can someone help here? I have Mazda mpv 2003, it just slipped down to zero motion from high speed (ATF is at maximum gauge) and since could not move in any of front Drive gears, but moves in Reverse gear. I have changed the ATF inside the gearbox and the fault remains as it is. Any help please!

    Reply
  • September 5, 2019 at 12:33 pm
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    You'll never catch me, Krabs! Not when I shift into MAXIMUM OVERDRIVE!!!

    Reply
  • September 5, 2019 at 1:04 pm
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    Sir please make Hindi this video

    Reply
  • September 5, 2019 at 5:42 pm
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    Not understand anything, but thanks

    Reply
  • September 5, 2019 at 5:54 pm
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    Engaging gears with out one grinding the other ,, this happen over long time development and upgrades, ,

    Reply
  • September 6, 2019 at 6:21 am
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    Brilliant

    Reply
  • September 7, 2019 at 9:56 pm
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    Do you have a video for a manual transmission of a Honda Accord LXI

    Reply
  • September 8, 2019 at 8:14 pm
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    I found this easier to understand than the manual one. wtf lol

    Reply
  • September 9, 2019 at 11:28 am
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    First video where planetary gearbox is explained that I understand how it really works..

    Reply
  • September 11, 2019 at 1:18 am
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    โ€œThis is the simplest form of an automatic transmissionโ€ nervous laughter

    Reply
  • September 12, 2019 at 5:22 am
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    Dunno why y'all are confused. Basically u input the shaft and off you go. Piece of cake.

    Reply
  • September 13, 2019 at 8:14 pm
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    I am young I donโ€™t understand

    Reply
  • September 15, 2019 at 7:10 am
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    This automatic transmission principle is 10x better than CVT transm…

    Reply
  • September 23, 2019 at 12:02 am
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    Whoever made this is clever. I just now began to understand how this works using leverage over the planetary gear systems. Still love my manuals though.

    Reply
  • September 24, 2019 at 4:31 pm
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    Eror 404, logic explanation not found !

    Reply
  • September 25, 2019 at 10:17 am
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    I was pretty good until 6th gear. I'm starting to get it now but it could do with a clearer explanation. From what I can understand, what's usually the output at the 2nd set (the carrier), is now used as the input for the sun gear which carries through to the sun gear for the 1st set, and since the ratio is reversed, the sun gear will be turning around 3 times as fast as the input speed (normally the carrier turns around a 1/3rd of the sun when the ring is stationary).

    Is this about right or have I misunderstood?

    Reply
  • September 25, 2019 at 4:26 pm
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    Can't understand this function in this life

    Reply
  • September 25, 2019 at 9:25 pm
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    Me 2019: ''I will NOT drive an automatic UNTIL I understand this video''
    Me 2030: (Still driving a manual)

    Reply
  • September 27, 2019 at 3:52 am
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    This guys so bad at teaching lol. Mute the video youโ€™ll understand it better.

    Reply
  • September 27, 2019 at 7:19 pm
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    I gave up after 30 seconds… Luckily there are people who are (a lot) smarter than me and are able to invent these things…

    Reply
  • September 27, 2019 at 11:09 pm
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    Obviously it's too satanic for be maked by humans. Don't be a naive materialists.

    Reply
  • September 30, 2019 at 12:04 pm
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    I still don't get it

    Reply
  • September 30, 2019 at 7:52 pm
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    But there are many different types of automatic transmission. I like the DuaLogicยฎ System from FIAT

    Reply
  • October 1, 2019 at 6:09 pm
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    I quit out of pornhub thinking I'll learn something new, should have stayed on there

    Reply
  • October 1, 2019 at 6:17 pm
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    1:41 Spin the ring gear in order get higher speeds.
    5:28 Hold the ring gear stationary in order achieve higher speeds.

    Reply
  • October 6, 2019 at 5:43 am
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    Lost

    Reply
  • October 6, 2019 at 9:14 pm
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    Show what the pistons look like that engage those clutch packs.

    Reply
  • October 7, 2019 at 1:34 pm
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    LMAO that drivetrain is hilariously small!

    Reply
  • October 10, 2019 at 3:09 am
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    Engineers who made manual transmission:๐Ÿค“

    Engineers who made automatic transmissions: "hold my beer."

    Reply
  • October 10, 2019 at 2:21 pm
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    Thanks for sharing Excellent Animation!

    Reply
  • October 11, 2019 at 1:37 pm
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    I've watched and rewatched this, the only thing that makes sense is why transmissions are so damn expensive

    Reply
  • October 13, 2019 at 1:38 pm
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    ๐Ÿ‘๐Ÿฟ๐Ÿค˜๐Ÿฟ

    Reply
  • October 14, 2019 at 4:37 am
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    Very simple it's how I make my living ๐Ÿ

    Reply
  • October 15, 2019 at 1:30 pm
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    If it's difficult for me to understand whats happening here, how about the guyz who came up with the initial design?

    Reply
  • October 20, 2019 at 4:44 pm
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    God my brain is burning like hell ๐Ÿ”ฅ

    Reply
  • October 20, 2019 at 4:53 pm
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    I'll go with CVT

    Reply
  • October 20, 2019 at 4:53 pm
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    I'll go with CVT

    Reply
  • October 20, 2019 at 5:05 pm
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    Ok by watching 4 times I understood 95% of it and by imagining in my mind for the rest of the night I hope I'll get the rest of the 5% too

    Reply
  • October 21, 2019 at 5:14 am
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    Does the engine tells an automatic transmission when to shift, or it shifts according to engine RPM, for e.g in a Nissan patrol 3.0 2004

    Reply
  • October 22, 2019 at 3:52 am
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    Honda transmissions do not work like this.

    Reply
  • October 23, 2019 at 8:21 am
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    ๐Ÿ“ฒ*00212645752301* *Whatapps*๐Ÿ“ฒ
    ูˆุฌู€ู€ุฏุช๐Ÿ’โ€โ™‚๏ธ ูƒู€ุซู€ูŠู€ุฑ ู…ู€ู€ู† ุงู„ู€ู€ูƒู€ู€ูˆู…ู€ู€ู†ู€ู€ุชู€ู€ุงุช ุนู€ู† ุชู€ูƒู€ุจู€ูŠู€ุฑ ุงู„ู€ู‚ู€ุถู€ูŠู€ุจ ูˆุถู€ุนู€ู ุงู„ุงู†ู€ุชู€ุตู€ุงุจ ูˆุณู€ู€ุฑุนู€ู€ุฉ ุงู„ู€ู‚ู€ุฐู
    ูˆุฃุจู€ุบู€ู‰ ุฃุจู€ู€ุดู€ู€ุฑูƒู€ู€ู…๐Ÿ˜‰ ุฃู†ู€ูŠ ุญู€ู€ุตู€ู€ู„ู€ู€ุช ุนู€ู„ู€ู‰ ู…ู€ู€ุนู€ู€ู„ู€ู€ูˆู…ู€ู€ุงุช ู…ู€ูู€ูŠู€ุฏุฉโœ… ู‡ู€ู€ุชู€ู€ู†ู€ู€ูู€ู€ุนู€ู€ูƒู€ู€ู… ูƒู€ุซู€ูŠู€ุฑ ูˆู…ู€ู€ุฌู€ู€ุฑุจู€ู€ู‡ู€ู€ุง ุดู€ู€ุฎู€ู€ุตู€ู€ูŠู€ู€ุง ูˆู†ู€ูู€ุนู€ุชู€ู†ู€ูŠ๐Ÿคฉ๐Ÿฅณ
    ุชู€ู€ูˆุงุตู€ู€ู„ ู…ู€ู€ุนู€ู€ูŠ๐Ÿ™‹โ€โ™‚๏ธ ูˆุฃู†ู€ู€ุง ุจู€ู€ุดู€ู€ุฑุญ ู„ู€ู€ูƒ ุณู€ู€ุฑ ุงู„ู€ูˆุตู€ูู€ุฉ ุงู„ู€ูˆุงุชู€ุณ ุงุจ *00212645752301*๐Ÿ“ฒ

    Reply
  • October 23, 2019 at 9:26 pm
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    All that time spent on computer animations and a great clear voice actor.
    Yet no one understands this at all.
    What the fuck do you mean just remove C4 and add C1?

    Reply
  • October 24, 2019 at 11:26 pm
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    All of this in my $500 piece of crap Chrysler,
    Engineers are truly underrated, their work is not valued at the level of ingenuity it takes to develop the technology we use for comfort.

    Reply
  • October 25, 2019 at 5:08 am
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    Amazing and clear video! Thank you so much!!! ๐Ÿ™‚

    Reply
  • October 28, 2019 at 2:27 am
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    I gotta be honest, this is my third time watching this, still have no idea whats happening…

    Reply
  • October 30, 2019 at 4:26 am
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    ummmm cant understand
    difficultes

    Reply
  • October 30, 2019 at 9:51 am
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    I was a physics major in college and there was definitely some stuff where I just accepted it and said well the numbers work out. This is one of those times.

    Reply
  • November 5, 2019 at 3:49 pm
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    I was feeling so demotivated that I couldn't understand the video but hey… I'm not alone ๐Ÿคฃ

    Reply
  • November 7, 2019 at 11:52 pm
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    Good video on auto transmissions. HORRIBLE voiceover! Obviously computer generated. NOBODY speaks with upward infliction on EVERY SENTENCE!

    Reply
  • November 8, 2019 at 8:00 am
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    nno sound

    Reply
  • November 10, 2019 at 1:57 am
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    Human enginuity never ceases to amaze me.

    Reply

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