What happens if you shift to R whiling driving 100 mph on the freeway?

[rc5]

Would you shoot backwards like a bullet?

 

[guyver01]

I think your tranny would keep going forward, while your car grinds to a halt.

 

[Amused]

<< Would you shoot backwards like a bullet? >>



Physics wasn't your strong point, was it?


This is what happens:

Your mechanic laughs at you while he replaces your transmission and collects $3000.

 

[phatcow]

dont forget to bend over nicely over the car jack cause its prolly not just the tranny thatll break.

 

[MadRat]

<<What happens if you shift to R whiling driving 100 mph on the freeway?>>

About 4 grand worth of repairs.

 

The driven wheels would lock and you would lose all control over the vehicle.

 

[Bulk Beef]

You would cause a rift in the space-time continuum. And you would start aging in reverse.

 

[Zenmervolt]

This might be a new sig... On a more serious note, if you shifted to reverse at just about any speed over say 5 mph, you would do at least some damage to your transmission. If you shifted to reverse at 100 mph, you would be introduced (rather roughly, I might add) to what is known colloquially as a "dropped transmission", which is to say that you would render your transmission (and very likely several other pieces of the drivetrain) completely useless. Of course, this is all just my theory, perhaps you could try it sometime and let me know what happens.

Zenmervolt

 

[spidey07]

most trannys have a lock that prevent you from doing it

 

[bunker]

The majority of newer vehicles won't let you shift into reverse at that speed.

 

[Pyroclazm]

most cars just shut off

 

[Amused]

<< The driven wheels would lock and you would lose all control over the vehicle. >>



No, not true. You'll hear a giant crunching and grinding noise as the gears in your tranny bounce off of each other, but it wont lock your drive wheels.

Same thing happens if you slam it in park.

edit: I know, because I've been in cars when this has been done. (NO, I didn't do it, a friend's mom did it when I was in 5th or 6th grade)

 

[SunnyD]

<< You would cause a rift in the space-time continuum. And you would start aging in reverse. >>



HA HA HA HA HE HEHEHEHEAHAHA!!!

Seriously, I'm laughing my arse off!

Umm... well, let's see. First off, more than likely your driveshaft will snap, you'll probably get whiplash from the sudden decrease in speed as the tranny locked up due to opposing force (I'm guessing that you'd probably get hit with about 30MPH of stopping force), the gears in your tranny would be toast, your clutch would be gone, and from therein you'd be coasting with a disengaged engine.

Best case scenario, about $5000-6000 worth of repairs on most cars. Worst case, you'll need a new car because if you do something as stupid as that you'll end up plowing into oncoming traffic after flipping your car over the median.

OTOH, your family might fare better with the insurance payment they get from your death...

SunnyD

 

Where are you people getting this info from ?

There are no safety devices on any car sold in America that prevents you from shifting into reverse at speed or that shuts the car down.

I am a 20yr ASE certified tech that has worked for almost every major automobile manufacturer and have never seen such a device.


No, not true. You'll hear a giant crunching and grinding noise as the gears in your tranny bounce off of each other, but it wont lock your drive wheels.

FALSE
Gears CANNOT grind in an automatic transmission.They are constantely meshed together in an assembly called a planetary gearset.When you shift a automatic transmission into gear,you are allowing hydrualic fluid to travel to pistons that actuate band clutchs which lock the planetary gears in place.

Please do not post about something you are guessing or know nothing about.

In a manual transmission,the gears are also in constant mesh together.When you shift a manual transmission,you are moving synchroniser rings which interlock on the INSIDE of the gear cluster,effectively locking then to the mainshaft,which transfers power to the output shaft.

 

[geno]

Someone had told me that you wouldn't be able to shift into reverse while going at high speeds since the teeth won't line up with the holes in the gears at that type of speed, I've never tested it though - I'm sure you'd get one hell of a grinding sound though.

 

[SludgeFactory]

Maybe we can get Britney Spears to test it out with her next rental car:

Britney Wrecks Ferrari

 

[Amused]

With an auto tranny, you can shift into R at speed. With a manual tranny, it's very hard to do, and every time you try you'll hear a grinding noise. You'd have to SLAM it in. At least, it's been this way with every stick I've owned.

 

[urameatball]

you are all wrong... the car will immediately go backwards at 100mph!!!

I know it'll stall and attempt to stop very abruptly... don't have any technical information on what would actually be damaged though.

 

[rickn]

Well, if you drive a manual transmission you know the sound they make when you downshift. I would imagine you would be hard of hearing if you managed to throw it in reverse at that speed

 

[Paulson]

Say goodbye to your tranny...

I did this the other day (actually I was pulling up to a stop to park, and put it in park at like 2 mph...) and got a little click click sound...

oh well, it still works and the lease is just about up

 

[rickn]

hehe, Yugo actually had a safety on the Yugo in order to throw it in reverse. To bad the rest of the car was a POS

 

[Zenmervolt]

Roger, I had thought that 1st and Reverse were unsynchronised on most transmissions, or am I simply about 20 years behind the times on that one? As far as an qutobox goes, you're absolutely correct, which is why the grinding I get from my old Honda's autobox when going from reverse to drive on a cold morning has been confusing me for the last 30,000 miles, if you have a tip on that I will be quite grateful by the way. Anyway, my real question was about synchromesh on 1st and reverse in a modern car. Oh, and don't most cars have some sort of lockout to prevent a direct 5th-Reverse shift? I know it could be bypassed by going from 5th to neutral and then to reverse, but I thought there was something to prevent a direct shift into Reverse. I know that my '76 Porsche 914 has a mechanism to prevent a 1st-Reverse direct shift (it has the old 901 transmission, I'll illustrate the shift pattern below).

R 2 4
| - | - |
1 3 5

Zenmervolt

 

[SpongeBob]

When I was 16 I had a car I didn't care about, and so I shifted into reverse(Auto Tranny) going 30MPH. The only thing that happened was that the car just completely shut off, electrical and everything. It kinda sucked because I lost the power steering and power brakes so I got real scared for a minute, but I just stopped, put it in park, started the engine and drove off. No biggie.

 

[rickn]

I believe my Mazda Millenia has a shift lock, it is an automatic. Once the car is moving, it is impossible to throw it in reverse

 

Zenmervolt
You can still shift it into reverse by first shifrting into nuetral and then by pushing down on the shift lever and forcibly slamming it into reverse with your foot on the clutch.
It is true that most cars do not use a synchronised reverse,but,you can still shift into reverse because these unsynchronised reverse gears have shift dogs in them.These dogs are nothing but slots cut into the inside of the gear cluster.
When you shift into reverse,a matching dog engages the inside of the reverse gear dog without the aid of a synchroser ring.
(A synchroniser ring has a simple job,to synchronise "Match the speed" of the rotating gears and output shaft.

There are shift interlocks on modern cars that prevent you from shifting out of park without first stepping on the brake.

The only thing preventing you from shifting into reverse is a shift lock,you must press a shift mounted reverse lock out button to engage reverse (Moving or not).