When I drove my first automatic the engine stalled at the first traffic light. It took me too many sweaty minutes to realize that you have to put it in neutral before you can start the engine again
![Phew :phew:](https://www.eevblog.com/forum/Smileys/default/phew.gif)
There must have been a problem with the engine then for it to stall. I have never known an automatic to stall its engine ever, so from that point of view they were safer.
You haven't driven many American cars from the 1970's and early 1980's, have you? Smog controls and carburetors. Stalling was all part of the fun. ![Banging Head |O](https://www.eevblog.com/forum/Smileys/default/bangheadonwall.gif)
But thats just it, with an auto, there is no clutch, you have a fluid flywheel with a torque convertor so the drive train was connected via the fluid flywheel which would slip when the car was stationary in drive because there was no clutch. Thats just how they were designed to do, whereas a manual you had to press the clutch down to disconnect the drive train to prevent the engine from stalling. So with an automatic, if it stalls, there has to be a reason for it stalling as the oil in the flywheel / torque convertor forms the clutch and is only too willing to slip when the drive train is prevented from turning due the brakes for example being applied and thus preventing the wheels from being driven.
Just to clear up a few misconceptions...
Modern automatics are automated multi-clutch manual gearboxes, they don't have torque converters.
They also won't start in Neutral, they have to be in Park.
The reason for the clutch interlock on a manual gearbox is to ensure the starter doesn't have to stir the gearbox when the oil is cold. This allows the battery and starter motor to be smaller, cheaper, and lighter. The apparent safety gain is purely coincidental, but makes for good advertising bullshit copy.
That is a dangerously broad generalization to make. ![Wink ;)](https://www.eevblog.com/forum/Smileys/default/wink.gif)
It suggests that they're a crashbox manual transmission, when in fact they're multistage planetary gearsets. Also, torque converters aren't going away anytime soon, no matter how much proponents of the CVT may try and sell us on the idea that torque converters are evil.
![](https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/?action=dlattach;attach=1176790;image)
The U760E in my wife's 2018 Rav4 uses a TCC locking torque converter; so does the Aisin AWF8F35 8-speed they (and half the rest of the world) are currently using when they're not still flogging the fucking rubber-band drive CVTs.
![](https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/?action=dlattach;attach=1176794;image)
And then of course, we have the ZF8 family representing Euoropean 8-speed engineering... again, a torque-converter design. These are just 3 examples of "modern" transmissions which still use a torque-converter. Yeah, okay... they may call it something else... but that's what it is.
Torque converters as used in modern vehicles are fucking magic. The losses of the olden slushbox days are just that... the olden days.
Modern torque converters have near-unity efficiency when locked, and the way they get more usable power to the ground, especially when coupled to a transmission with a decently broad set of gears that match a motor's power curve, has made them generally more efficient than a manual for decades now, aside from the rare example of drivers using the most ardent hi-miler driving techniques.
mnem
![Tweak :-/O](https://www.eevblog.com/forum/Smileys/default/smiliey_cal.gif)