# What exactly does the button on the "shifter" in an automatic do? **URL:** \ **Category:** Factual Questions\ **Created:** [December 21, 2004, 7:21pm UTC](https://boards.straightdope.com/t/what-exactly-does-the-button-on-the-shifter-in-an-automatic-do/281019 "2004-12-21T19:21:01Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![SmackFu](https://avatars.discourse-cdn.com/v4/letter/s/53a042/32.png) [@SmackFu](https://boards.straightdope.com/u/SmackFu)\ **Post date:** [December 21, 2004, 7:21pm UTC](https://boards.straightdope.com/t/what-exactly-does-the-button-on-the-shifter-in-an-automatic-do/281019/1 "2004-12-21T19:21:01Z")
Mine is currently doing nothing. I can change from Park to Drive without pushing it. I’m wondering how bad that is. Is it just a lock, to prevent you knocking the lever into some very bad gear, or does it have some other purpose? ---
**Author:** ![gotpasswords](https://avatars.discourse-cdn.com/v4/letter/g/c57346/32.png) [@gotpasswords](https://boards.straightdope.com/u/gotpasswords)\ **Post date:** [December 21, 2004, 7:34pm UTC](https://boards.straightdope.com/t/what-exactly-does-the-button-on-the-shifter-in-an-automatic-do/281019/2 "2004-12-21T19:34:37Z")
Big mechanical sort of button that’d right under your thumb? That’s \*supposed \* to be a safety to keep the shifter from vibrating or being knocked out of Park. It really is a good thing to have - otherwise, your car could take off on its own if the engine’s running. Smaller non-mechanical button lower down on the shifter? Likely to be an overdrive on/off control. At least that’s how the two buttons on my Jeep’s console shift behave. ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [December 21, 2004, 7:42pm UTC](https://boards.straightdope.com/t/what-exactly-does-the-button-on-the-shifter-in-an-automatic-do/281019/3 "2004-12-21T19:42:46Z")
On many cars there is also a small button which is a mechanical override for the shift inhibit solenoid. This is the device that prevents you from shifting out of park unless your foot is on the brake. If the switch in the brake pedal or the solenoid itself fails, you can’t get the shifter out of park. Ever. So, they put a button on there so you can force it out of park if the thing breaks. ---
**Author:** ![SmackFu](https://avatars.discourse-cdn.com/v4/letter/s/53a042/32.png) [@SmackFu](https://boards.straightdope.com/u/SmackFu)\ **Post date:** [December 21, 2004, 9:46pm UTC](https://boards.straightdope.com/t/what-exactly-does-the-button-on-the-shifter-in-an-automatic-do/281019/4 "2004-12-21T21:46:08Z")
> [@gotpasswords](#): > > Big mechanical sort of button that’d right under your thumb? That’s \*supposed \* to be a safety to keep the shifter from vibrating or being knocked out of Park. Yeah, that one. So maybe it’s just mechanically broken somehow. ---
**Author:** ![Acsenray](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/acsenray/32/4519_2.png) [@Acsenray](https://boards.straightdope.com/u/Acsenray)\ **Post date:** [December 21, 2004, 10:03pm UTC](https://boards.straightdope.com/t/what-exactly-does-the-button-on-the-shifter-in-an-automatic-do/281019/5 "2004-12-21T22:03:52Z")
Note that in many cars, failure to press the button will not prevent you from shifting the car from drive to neutral and back. ---
**Author:** ![Gary\_T](https://avatars.discourse-cdn.com/v4/letter/g/3ec8ea/32.png) [@Gary\_T](https://boards.straightdope.com/u/Gary_T)\ **Post date:** [December 22, 2004, 4:35am UTC](https://boards.straightdope.com/t/what-exactly-does-the-button-on-the-shifter-in-an-automatic-do/281019/6 "2004-12-22T04:35:37Z")
It’s not only to prevent unintended shifting into and out of park, but also to prevent certain other unintended shifts (e.g. into low and into reverse). ---
**Author:** ![Hail\_Ants](https://avatars.discourse-cdn.com/v4/letter/h/dc4da7/32.png) [@Hail\_Ants](https://boards.straightdope.com/u/Hail_Ants)\ **Post date:** [December 22, 2004, 4:52am UTC](https://boards.straightdope.com/t/what-exactly-does-the-button-on-the-shifter-in-an-automatic-do/281019/7 "2004-12-22T04:52:26Z")
> [@](#): > > It’s not only to prevent unintended shifting into and out of park, but also to prevent certain other unintended shifts (e.g. into low and into reverse). It only prevents the shifter from going up into reverse & park. Try it with the engine off. You can shift up & down thru N D 3 (if you have OD) 2 and 1 but there’s a catch preventing it from going up into R or P (or from R into P) unless you’re pushing that button in. Automatic transmissions have internal electronic and/or hydraulic controls which prevent them from downshifting if the speed is too high even if you move the lever into a lower number. That button is a completely separate mechanism from the brake pedal solenoid lock. It’s just a one-way racheting lock completely contained within the shifting lever. ---
**Author:** ![Gary\_T](https://avatars.discourse-cdn.com/v4/letter/g/3ec8ea/32.png) [@Gary\_T](https://boards.straightdope.com/u/Gary_T)\ **Post date:** [December 22, 2004, 6:16am UTC](https://boards.straightdope.com/t/what-exactly-does-the-button-on-the-shifter-in-an-automatic-do/281019/8 "2004-12-22T06:16:11Z")
> [@Hail Ants](#): > > It only prevents the shifter from going up into reverse & park. Try it with the engine off. You can shift up & down thru N D 3 (if you have OD) 2 and 1 but there’s a catch preventing it from going up into R or P (or from R into P) unless you’re pushing that button in. That may be true on your car, but it’s not the case with most. For example, a '92 Taurus requires using the release for the following shifts: P\>R, P\D, D\>2, & 2\>1. ---
**Author:** ![JRDelirious](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jrdelirious/32/9531_2.png) [@JRDelirious](https://boards.straightdope.com/u/JRDelirious)\ **Post date:** [December 22, 2004, 2:58pm UTC](https://boards.straightdope.com/t/what-exactly-does-the-button-on-the-shifter-in-an-automatic-do/281019/9 "2004-12-22T14:58:19Z")
> [@engineer\_comp\_geek](#): > > On many cars there is also a small button which is a mechanical override for the shift inhibit solenoid. . However, the override switch is usually tucked away where you have to actually be making an extra effort to activate it. The big thumb button is a detent to keep you from shifting to the wrong setting (as defined by the maker) by accidental bumping of the stick. Column-mounted auto shift levers achieve that by a mechanism that requires you to pull the stalk towards you in order to move it. ---
**Author:** ![Hail\_Ants](https://avatars.discourse-cdn.com/v4/letter/h/dc4da7/32.png) [@Hail\_Ants](https://boards.straightdope.com/u/Hail_Ants)\ **Post date:** [December 23, 2004, 3:47am UTC](https://boards.straightdope.com/t/what-exactly-does-the-button-on-the-shifter-in-an-automatic-do/281019/10 "2004-12-23T03:47:31Z")
> [@](#): > > That may be true on your car, but it’s not the case with most. For example, a '92 Taurus requires using the release for the following shifts: P\>R, P\D, D\>2, & 2\>1. You are correct. Don’t know why I thought it didn’t stop you from going further down than D. Although on most cars I’ve driven you _can_ move the shifter back & forth thru 1, 2, and 3 (if an OD) without using the button. Except for real fancy sports cars that have locking gate shifters for drag racing