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Old 24th May 2008, 11:56   #46
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Since the reverse gear is not synchromesh for most cars, is it at least theoretically possible to shift into reverse without stopping?
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Old 24th May 2008, 23:56   #47
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Having read through the thread, I still don't understand why anyone would want to try doing this at all?? A theoritical discussion is fine, and when that tells you it will destroy the gearbox, why would anyone want to test that theory?
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Old 25th May 2008, 15:01   #48
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In theory it should be possible.

Maybe its for doing that sequence in SAAB.



See in the 52sec.
Amazing stuff

Last edited by Rehaan : 25th May 2008 at 21:00. Reason: No problem.
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Old 25th May 2008, 21:12   #49
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Quote:
Originally Posted by yzfrj View Post
In theory it should be possible.
Hey,

Good find there yzfrj.
However, in the video the driver is not really shifting to reverse at high speed.
Even though the car is moving (regardless of how fast its moving) he has his wheels locked when he makes the shift to reverse. So essentially it is like shifting into reverse if the car was at a standstill.

cya
R
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Old 7th August 2008, 23:28   #50
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Quote:
Originally Posted by kartikkumar View Post
Having read through the thread, I still don't understand why anyone would want to try doing this at all?? A theoritical discussion is fine, and when that tells you it will destroy the gearbox, why would anyone want to test that theory?
kartik, the question is not about wanting to try but rather a concern for safety of the car as well as user, IMHO. This concern and fear of accidentally engaging reverse gear while in forward motion have been in the back of my mind since yesterday. Thanks to this thread, my doubts are cleared. Well, almost. I still wonder if my car has some sort of reverse gear lock (not the pin or 'U' type ) that would make it absolutely impossible instigate those gnashing teeth warning.
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Old 11th October 2009, 22:25   #51
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As I had mentioned elsewhere, I am driving my new Alto after a lay off of a decade. The car I last had was a Dolphin and all the cars I had driven till then had 4th as top. So engaging reverse from top was not possible.

Now I constantly have this fear at the back of my mind as the Alto has 5 gears. Very recently I accidentally pulled the lever in to R from 5th (instead of 4th), and as soon as I started releasing the clutch I heard a shrill noise. So immediately depressed the clutch and slotted to 3rd and then shifted to 4th. It took me a while to compose myself when I realized what I had almost done. Hope it has not caused any harm!

It should not be possible for this to happen. There must be a safety device to prevent this.
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Old 11th October 2009, 23:01   #52
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why in the world would you want to do it...?
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Old 11th October 2009, 23:04   #53
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Quote:
Originally Posted by garry.brant View Post
why in the world would you want to do it...?
I did not "want" to do it (who would?). I said it was accidental. And it should not happen even accidentally, the system must be fool proof.
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Old 12th October 2009, 00:20   #54
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I dont think its possible. Since the reverse gear makes the shaft rotate the other way around, it would be impossible to shift into reverse (atleast when the car is moving forward).

But if a car is rolling backwards in neutral, there might be a chance of shifting it into reverse with some crafty revv matching.

And lets not consider stunt cars here, as they are highly modified to do such things.

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Last edited by Shan2nu : 12th October 2009 at 00:25.
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Old 12th October 2009, 02:58   #55
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I think there is no sense of this thread. It should have been locked in the first place. Sorry if im sounding rude but i am not. Anybody worth his salt knows that one can do many things but should one do it.

Its like asking, can one jump of a plane from 4000ft without a parachute??

Sure one can, but will one??

So also sure one can shift i the reverse at high speed but will one?

Now that its clear that if this senseless manoeuvre is tried, it will lead to a broken gearbox. So what is the point of this thread?
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Old 12th October 2009, 03:20   #56
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Quote:
Originally Posted by CrAzY dRiVeR View Post
Since the reverse gear is not synchromesh for most cars, is it at least theoretically possible to shift into reverse without stopping?
No. In reverse gear the driving gears will be rotating in one direction and the driven gears in the opposite direction. And no synchromeshing on reverse gear. Result will be a shattered gearbox. Due to this some vehicles will have a lock on the reverse gear to prevent shifting into reverse accidently.
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Old 12th October 2009, 03:34   #57
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sorry, if this is mentioned earlier. I have heard that some cars like GM have some kind of extra lever or something to make slotting into reverse foolproof. In my car (baleno), there is a different safety mechanism. You can not go from 5th to reverse directly, you have to bring the gear lever to the center of neutral line first and only then putting it into reverse position is possible. That significantly reduces probability of accidental reverse. (It never happened to me at least in close to 4 years!)
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Old 12th October 2009, 07:34   #58
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Quote:
Originally Posted by V-16 View Post
So also sure one can shift i the reverse at high speed but will one?
So what is the point of this thread?
A novice driver can do this accidentally, can't he? So what is the point in asking "who will want to do it"?

My point is, in the 4 gear cars this would be impossible. 5 gears came later and should have some means to prevent this. I am sure there are some cars which have such a mechanism.
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Old 12th October 2009, 10:11   #59
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5 speed transmissions have an interlock to prevent shifting from 5th to reverse directly, it is not possible to shift into reverse from 5th gear unless shifting to neutral first.

Last edited by jav : 12th October 2009 at 10:12.
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Old 12th October 2009, 10:17   #60
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Of course it is certainly possible to shift into reverse gear when you are travelling at high speed in the forward direction! Provided of course you're prepared to wrestle a bit with the vehicle (it has to be an older vehicle though since the new ones have some kind of preventive system.)

Only - be prepared to deal with a complete set of beautifully stripped gears and gear box as well as a ruined differential gear system which of course will be on holiday forever forthwith, along with a wrecked vehicle.

Oh - I forgot - it might be handy to wear ear-plugs (unless of course you like hearing the sound of wrenching metal), a helmet and fire proof gear as well as carry an extinguisher etc with you while attempting such interesting maneuvres.

And last, but not least, do please extend a ring side seat invite to us other BHP chaps so we can applaud your courage as well as be on hand for any help you may need!

Sarcasm and jokes apart my friend, I fail to understand the purport of the query.

Do let us know!

Happy Diwali in advance!

Last edited by shankar.balan : 12th October 2009 at 10:23.
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