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Old automatic transmissions — Parallax Forums

Old automatic transmissions

I was looking to the pictures in volocars.com and the automatics have: P, R, N, D, 2 and 1. How do you drive that ? Do you have to start in 1, then 2 and then D ? just curious.

Comments

  • evanhevanh Posts: 15,916
    What are you comparing against, Ale? I've almost never touched any automatic vehicles but that one is still an easy answer - (D)rive is all gears. And always has been for automatic (and lookalikes) vehicle transmissions. The 1 and 2 positions were only if you are wanting to hold it in a specific lower gear - Typical of an automatic three-speed fully mechanical gearbox.

    The Tiptronic (Pretend auto gear sticks) system usually goes further and allows easy holding/selecting any gear because it uses an electrically driven gear selector. Tiptronic still has the Drive position.

    For a bit of trivia; Sequential is the name for electrically driven gear selector when it's a manual gear box. Sequential's also exhibit a Drive position now too. As do CVT's.
  • AleAle Posts: 2,363
    Thanks for clarifying. I was not comparing it to anything, just curious on why there was what I though (and you confirmed) 1st and 2nd gear.
    I know newer automatics, they have only D, but you can also manually change gears. Where I work, we develop 8 and 9 gears automatic transmissions, they do not have fixed positions afaik, but I only see a tiny bit from the whole :)
  • As Evan says, you put it in Drive and leave it there. The 1 and 2 gears are only for going up steep grades, etc.
  • ercoerco Posts: 20,256
    edited 2016-08-06 16:50
    I've rebuilt Ford C4s, Chrysler Torqueflites and a Corvair Powerglide. Marvelous creations all. The bottom-most valve body is a sophisticated fluid mechanical computer with both analog and digital functions. BTW '2' is a range, 1-2. It starts in first gear, then shifts to second, but not third gear. Forces a downshift from third gear for braking.
  • As Evan says, you put it in Drive and leave it there. The 1 and 2 gears are only for going up steep grades, etc.

    Or when you going downhill towing a trailer and your brakes are failing. :)

  • evanhevanh Posts: 15,916
    edited 2016-08-06 23:42
    Ale wrote: »
    ... Where I work, we develop 8 and 9 gears automatic transmissions, they do not have fixed positions afaik, but I only see a tiny bit from the whole :)

    Ah, I do wonder if maybe you are dealing with a sequential rather than an tiptronic(automatic) ....? I say this because, with that many gears, it sounds like you might be talking about transport trucks or buses or similar, ie: much heavier vehicles than what the consumer buys.

    PS: It's important to make the distinction between automatic and tiptronic here, because sequential is the manual transmission's equivalent name.
  • AleAle Posts: 2,363
    We make tiptronic :), it comes with several different names depending on the make. The ones I saw for trucks have like 16 gears :).

    What I meant with "fixed positions" was regarding the gear lever, that it only has D for forward (besides sport and so on).
  • erco wrote: »
    I've rebuilt Ford C4s, Chrysler Torqueflites and a Corvair Powerglide. Marvelous creations all. The bottom-most valve body is a sophisticated fluid mechanical computer with both analog and digital functions. BTW '2' is a range, 1-2. It starts in first gear, then shifts to second, but not third gear. Forces a downshift from third gear for braking.

    Unless you get into older transmissions like a 1965 C4 transmission. It has a low gear for only low but for drive it uses dots. The first position up from L is really normal drive instead of the one above it. Definitely not what I was use to.

    Robert
  • ercoerco Posts: 20,256
    edited 2016-08-07 21:18
    Dots? You mean dots instead of numbers? Funky.

    Chevy's Powerglide tranny only had 2 speeds, low & drive.

    Fun facts:

    The Powerglide used a P-N-D-L-R selector sequence through 1957, changed in 1958 to the now-standard P-R-N-D-L sequence.

    The special Corvair version (rear engine) had no PARK position and a dash-mounted shift lever:

    shifter.jpg

    Some high-end cars had push-button "Select-O-Matic" tranny controls:

    1963PlymouthFurya.jpg





  • erco wrote: »
    Dots? You mean dots instead of numbers? Funky.

    Yep. It has L for 1st only, Normal Drive is where second should be and the Dot where drive is actually starts out in 2nd gear. Took me a while to get used to it. There is a note about it here:

    "It is commonly referred to as the "green dot" C4 (used up to 66). What would be the normal drive position is actually a 2nd gear take off mode (for snow,etc.), and what would normally be the 2nd gear position is actually normal automatic drive mode (1,2,3). 1st gear position remains the same, first gear only,"
  • ercoerco Posts: 20,256
    edited 2016-08-07 21:26
    "It is commonly referred to as the "green dot" C4 (used up to 66).

    When I hear "green dots" circa 1966, I see this:

    a200.jpg

  • ercoerco Posts: 20,256
    Some interesting comments on the variety of car controls near the end at http://www.ford-trucks.com/forums/842726-why-hasnt-the-select-o-matic-transmission-reappeared.html

    Handbrake style levers controlled overdrive, hood release, and gearshift on various old cars. Thankfully for safety, transmission shifters & shift patterns became fairly standardized in the 1960s. Not sure if it was government intervention or not, but overall a good thing.

    The tragic recent death of Anton Yelchin (Chekov in Star Trek reboot) may be due to a faulty shifter design: http://www.people.com/article/anton-yelchin-dead-jeep-recall-gear-defect
  • evanhevanh Posts: 15,916
    edited 2016-08-08 06:17
    Ale wrote: »
    What I meant with "fixed positions" was regarding the gear lever, that it only has D for forward (besides sport and so on).

    Right, so that's the difference between a fully mechanical gear lever, where there is more complexity at the interface to the operator, verses Tiptronic, where the electrical shifter can hide it all inside the gearbox.

    The physical gear lever for Tiptronic is just a gimmick.
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