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I drive a Toyota Corolla (E120, year 2000). It has automatic transmission with these options: P, R, N, D, 2, L. I almost always drive using "D". If I am driving at around 70 km/h (e.g. on level road or down a hill), is it safe to shift from "D" to "2" or "L"? Does the answer depend on whether or not I am pressing the gas pedal and/or accelerating while shifting?

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  • It's not advisable selecting 2 (2nd gear) at speeds above approximately 32kph or redline on the tachometer. Selecting 2 or 1 keeps the transmission in that gear until you shift back to D mode for automatic shifting of gears.
    – F Dryer
    Commented Sep 23, 2023 at 14:15
  • If you are descending a steep hill where you need a lower gear to help with the braking, first slow the car with the brakes to the safe speed and then engage the lower gear. Its purpose is to stop the gearbox shifting back up when there is no power demand from the engine. Those antiquated designs are not very clever. A modern DSG gearbox would probably figure this out for you, and the purpose of its gear hold is mostly marketing. Commented Sep 23, 2023 at 18:18

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While I am not familiar with this particular car, I would not think twice to gear down an automatic transmission if I'm going downhill and I need engine braking.

It is up to the transmission control mechanism to prevent the engine from going into unsafe rpm numbers. This means that you may or may not get the braking action expected, no matter how much important is this for you.

Anyway, the signs 1/2/3/L on the stick do not mean anymore "limit to the 1/2/3/lowest gear". What these mean on a model year 2000 or newer car is simply "I need my engine more responsive right now and I am ok with the increased fuel usage, wear and noise, so switch gears at higher rpm, please".

If you don't like this, drive manual. 20-ish percent better economy and a marginal possibility to break your engine by shifting gears.

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  • It is up to the transmission control mechanism to prevent the engine from going into unsafe rpm numbers. I think this is incorrect. It's up to the driver to follow the instructions in the manual. On my old automatic Toyota, if you threw it into low gear while moving fast, it would redline, possibly damaging the engine. Of course, if the brakes aren't working, it might well be worth it. Commented Sep 24, 2023 at 21:51
  • @RockPaperLz-MaskitorCasket How much old is your old Toyota? 2000+ or way older? Manuals are good (joke!), but few people read them and even those who do sometimes do especially stupid things. I used Toyota (not Corolla) from 1996 or 1998 and it was pretty much OK to gear down at any speed. My 2002 Chrysler Grand Voyager (much lower tech than any Toyota from 2000) is safe either - otherwise, either I or my equally manual-trained wife would break it at the first downhill.
    – fraxinus
    Commented Sep 25, 2023 at 6:32
  • That Toyota was from 1988, IIRC. That's newish, right? ;) I initially missed the part in your answer referring to model year 2000 or newer. How certain are you about your claim? If you're pretty certain, I'll add it to my brain as "possibly correct useful new information learned from an online stranger". :) In all seriousness, if you're correct, that's a big (and most welcome) improvement to automatic transmissions. And I'm grateful to you for learning about it here. Commented Sep 26, 2023 at 7:41
  • @RockPaperLz-MaskitorCasket I am pretty sure about anything that has electronically-controlled automatic transmission (i.e. solenoids inside the box) and also anything that has "hydraulic logic" (whatever the manufacturer calls it). The technology changeover is somewhere before the year 2000, but I am an European and I avoid automatics by instinct so I don't know the exact year per brand.
    – fraxinus
    Commented Sep 27, 2023 at 6:29
  • Thanks. I'll keep my eyes out for those buzzwords. Because most rental vehicles are relative new (typically newer than model year 2000) and have automatic transmissions (for better or worse), it's good to learn that they will likely incorporate this "modern" technology. Commented Sep 27, 2023 at 8:42

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