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LTC8K6 said:
With an auto, when I back up I hit neutral once I get going, then I stop, then into drive. To people who don't realize, it looks like I am putting it in drive while rolling backwards, but I'm actually just hitting neutral, which shuts off the reverse lights.
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Why the hell would you do that. If you're going to stop anyway after reversing then it doesn't take any longer to go straight to drive nor does it do any damage.
 
i havent had to double clutch anything since my old mid 60s delivery van i used to drive for work back in the 80s. my older datsun cars never had an issue putting it into 1st under 20mph either, and either does my 01 dodge ram truck. double clutching isnt really necessary anymore. that said, ive rarely found a reason to put it into 1st while going anywhere near 10mph. when im coasting to a stop ill drop it in when im about to stop. 2nd gear starts are very easy at 5-10mph
 
Automatic transmissions have a torque converter. The only thing that reversing, throwing it into drive and hitting the gas while still moving backwards is going to do is heat your transmission fluid slightly.

In a manual, doing this will cause slightly increased clutch wear.
 
Demo24 said:
Why the hell would you do that. If you're going to stop anyway after reversing then it doesn't take any longer to go straight to drive nor does it do any damage.
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It's quicker. I have to go through N anyway. Plus, it's a habit I developed from driving older cars with bands that would break if you went into D while still rolling backwards.
 
2006+ Subarus have dual synchros for 1st making it very easy, prior years are notorious for refusing the ol' 2->1.
 
LTC8K6 said:
With an auto, when I back up I hit neutral once I get going, then I stop, then into drive. To people who don't realize, it looks like I am putting it in drive while rolling backwards, but I'm actually just hitting neutral, which shuts off the reverse lights.
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Why in the hell would you do that? Not only does it not give you any benefit what-so-ever, but it's also very dangerous. If people don't see your reverse lights and you're going at a very slow speed, it might not look like you're moving at all. Do that in a parking lot and you're going to get yourself hit, hopefully not by me because I'd be extremely pissed that I just hit some idiot who thought he was cool because he could back up in neutral.
 
Eli said:
Automatic transmissions have a torque converter. The only thing that reversing, throwing it into drive and hitting the gas while still moving backwards is going to do is heat your transmission fluid slightly.

In a manual, doing this will cause slightly increased clutch wear.
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This sound about right to me too, but could there be other factors at play here?

Any mechanics or transmission specialists here? I know car owner's manuals recommend that the wheels be stationary before switching from reverse to drive, but car owner's manuals also insist there exist such things such as "lifetime fluids".

What's the real deal here?
 
reallyscrued said:
This sound about right to me too, but could there be other factors at play here?
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It's bad for the transmission itself. Normally when you shift from 1 to 2, you're disengaging one gear then engaging another gear. Reverse is not like that at all. Reverse means one gear is engaged, then the reversing gear is engaged in addition to that. Ideally you are supposed to do this when the gear speeds are synchronized, and the gears are synchronized when the car is stopped. Switching between forward and reverse while the car is rolling is equivalent to driving a manual and changing gears without using a clutch and without synchronizing the speeds. *grind*

In an automatic, a few things can happen. One is that the car makes a loud BANG noise when it changes directions. That's the sound of your transmission expressing how much it dislikes you. Another possibility is that it simply grinds away the clutches inside the transmission and you don't realize it's damaging it. Another possibility is that the electronically controlled transmission will not attempt to change direction until the speed is within an acceptable speed range.

In every manual transmission I've driven, one cannot change direction while it's rolling. It just doesn't allow the stick to move into any of the forward gears while it's rolling backward. When mythbusters tried doing it the other way around, forward to reverse, the same thing happened to their manual. It'll make a bunch of grinding noise but it will not change no matter how hard you want it to.
 
ShawnD1 said:
It's bad for the transmission itself. Normally when you shift from 1 to 2, you're disengaging one gear then engaging another gear. Reverse is not like that at all. Reverse means one gear is engaged, then the reversing gear is engaged in addition to that. Ideally you are supposed to do this when the gear speeds are synchronized, and the gears are synchronized when the car is stopped. Switching between forward and reverse while the car is rolling is equivalent to driving a manual and changing gears without using a clutch and without synchronizing the speeds. *grind*

In an automatic, a few things can happen. One is that the car makes a loud BANG noise when it changes directions. That's the sound of your transmission expressing how much it dislikes you. Another possibility is that it simply grinds away the clutches inside the transmission and you don't realize it's damaging it. Another possibility is that the electronically controlled transmission will not attempt to change direction until the speed is within an acceptable speed range.

In every manual transmission I've driven, one cannot change direction while it's rolling. It just doesn't allow the stick to move into any of the forward gears while it's rolling backward. When mythbusters tried doing it the other way around, forward to reverse, the same thing happened to their manual. It'll make a bunch of grinding noise but it will not change no matter how hard you want it to.
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1) An automatic uses a planetary system, not a traditional twin shaft arrangement. This means that reverse in an automatic is achieved in a completely different manner from what you have described. It will absolutely not "grind away the clutches" (for one, clutches don't "grind", and for another the increased wear on the clutchpacks is relatively slight unless if you're only moving at 1-2 mph). In most modern electronically-controlled automatics, the transmission electronics won't even allow the shift until it's safe for the mechanical bits anyway. (How a planetary gearset achieves reverse.)

2) You can easily shift out of reverse while in motion, it's shifting into reverse that's problematic because reverse is not synchronized. Shifting out of a non-synchronized gear is just as easy as shifting out of a synchronized gear. Since the forward gears are synchronized (in modern manuals), you can shift into 1st while the car is moving backwards. However, this is harder on the 1st-gear synchro (which is weaker than the other synchros in most transmissions remember) and it's difficult at speeds above say 1-2 mph.

ZV
 
my transmission (2006 g35 6sp) locks me out of 1st if the car is moving, and 2nd at far too low a speed. i find it much more annoying than the speed limits placed on 1st (20) 2nd (30) and 3rd (40). i still adore the car, and consider it a lesson learned.
 
I tried to rev match before using firsts when I had to pass through some bumps this week but I couldn't match it right and lost more time, the gear engaged on the second try at idle while moving slowly which I think confirm the weak Syncro on 1st gear (my car is not tall for this kind of bumps).

I can use 2nd but I need to rev the motor and disengage the clutch slowly which annoys me because I think I'm wearing it because my lack of expertise if I disengage it faster at low RPM the car starts to tremble.
 
Most I've downshifted to 1st is ~35mph, just have to rev match.

Would be worthless if I couldn't get into 1st at lower speeds when 1st redlines about 50mph.
 
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