Question about manual tranny

[Argo]

Something I was always wondering but was too afraid to try. What happens if you accidentally shift into lower gear than you were supposed to. For example instead of shifting into 3 you shift into 2nd or 1st. Will that damage the tranny/engine or is some sort of safety mechanism going to kick in?

 

[Scarpozzi]

Some of them have a safety mechanism and won't shift into the gear. The old ones make the grrrrrrrr sound as the car decellerates....

 

[Nemesis77]

Well I can't imagine anyone making that by mistake. But it can be done intentionally in order to decelerate the car without braking.

 

[StageLeft]

I think he means let's say 1st gear goes to 30 mph and 2nd goes to 60 and instead of shifting into 3rd when you're at 60 by mistake you shift into 1st which would jack your RPM to over 10k.

 

[Banana]

There's no safety mechanism, except maybe for preventing you into shifting into first. The effect of downshifting will depending on how fast you're going. Obviously, the greater the initial speed at the time of the "mistake," the higher the RPMs will be at the lower gear, and the greater the slowing effect is on your speed. If you release the clutch gradually, you'll notice that something is wrong and that will give you time to shift into the correct gear. If you're bad with the clutch, the car will jerk to a sudden lower speed, and your motor will suffer.

I use downshifting to slow down gradually. If I'm slowing to a halt, I shift from 5th to 2nd, or 4th to 2nd. The key is smooth clutch action.

 

[SinfulWeeper]

If your going fast enough, there would be no way for you to get it in a lower gear till you slow down... unless you are actively trying.

 

[mrCide]

when i slow down i usually shift into fourth/third and slowly let upp on the clutch (not all the way) then throw it into neutral, or if im turning and need to go into 2nd i may rev match

 

[Elbryn]

your engine goes VROOOM really loud as you suddenly go into higher revs.. typically you'll jerk a bit and then you instinctively hit the clutch again and shift into another gear.

 

[Quixfire]

The greater risk my shifting into a lower gear is over revving the engine. My brother did this and bent a intake valve and broke a valve spring. He went from 3rd to 2nd and went over the red line.

 

[Banana]

Originally posted by: Quixfire
The greater risk my shifting into a lower gear is over revving the engine. My brother did this and bent a intake valve and broke a valve spring. He went from 3rd to 2nd and went over the red line.

:Q He must have been close to redline at 3rd . . . I seldom venture anywhere close to redline

 

[aswedc]

Originally posted by: Nemesis77
Well I can't imagine anyone making that by mistake. But it can be done intentionally in order to decelerate the car without braking.

I did it a couple times when I was first learning...the car goes

1 3 5

2 4 R

I would be trying to go from 3 to 4 and put it in 2...

 

[Demon-Xanth]

Depends on the car, engine and transmission. I've determined that at 55MPH dumping the clutch in 2nd (it redlines at 60MPH) while decelerating will slide the rear tires, same thing with third (redline at 105) at 75MPH. Some cars, notably the RSX will overrev and potentially blow the engine.

 

[WinkOsmosis]

I've had that happen. It was shifting into 3rd instead of 5th though. I let the clutch out slowly though, so I noticed before rpms got too high and shifted.
One time I was racing a Suburban and shifted into 5th instead of 3rd, which is even more catastrophic... to my pride!! Nah, not really.

 

[Thegonagle]

There is no active safety mechanism for any gear in any street car that I know of. The only ?safety mechanism? is that that the higher speed you ask the synchronizer to spin the input shaft up to, the more pressure you will need to put on the shift lever, so that makes it somewhat difficult to spin the input shaft up to 10,000 RPM.

Originally posted by: Demon-Xanth Some cars, notably the RSX will overrev and potentially blow the engine.

Ah, you saw that video too? The fact is, that will happen on any car if you?re a meathead who probably shouldn?t even shift a three speed bike. There is nothing special, different, or wrong with the RSX.

 

[Vic]

Done right, you get a nice compression lock. Done wrong, you break something.

 

[m2kewl]

Originally posted by: Argo
Something I was always wondering but was too afraid to try. What happens if you accidentally shift into lower gear than you were supposed to. For example instead of shifting into 3 you shift into 2nd or 1st. Will that damage the tranny/engine or is some sort of safety mechanism going to kick in?

like others have said, it depends on the car. high end performance cars will usually go up to around 50mph before needing to go to 2nd gear - so what's there to downshift?

on "normal" cars, just don't drop it into 1st when moving. a lot of experienced people will engine break (downshifting) to slow down/get more power, so lowering gear is not really accidental. you just need to be aware of your speed and gear position.

 

[Demon-Xanth]

Originally posted by: Thegonagle

Ah, you saw that video too? The fact is, that will happen on any car if you?re a meathead who probably shouldn?t even shift a three speed bike. There is nothing special, different, or wrong with the RSX.

The main difference is a low reving, high torque, rear wheel drive truck vs. the high reving, low torque, front wheel drive car. It gets more traction on it's drive wheels under breaking whereas my truck gets less. Also, I was discussing this with some gear heads last week and they were pretty much agreeing that rev limiters will make it more likely to slide tires than over rev. The RSX has no limiter, my truck has one at 6,000.

 

[Thegonagle]

All a rev limiter does is cut off the fuel, which prevents the engine from making power beyond the point it's set at. The RSX does have one of those. All fuel injected Hondas do. But a rev limiter isn't going to do a thing when some meatball shifts to second at 90 MPH and engages the clutch, which connects the engine directly to the transmission, which at this point, is spinning 50% faster than the redline (assuming a redline in 2nd gear at 60 MPH). That's simply beyond the capability of fuel cut-off.

 

[notfred]

If you accidentally hit 2nd instead of 4th in my car, you'll slow the back wheels down enough to get the tires to screech. It's like a reverse burnout or something.

 

[skateallday]

Originally posted by: 1YellowPeril
There's no safety mechanism, except maybe for preventing you into shifting into first. The effect of downshifting will depending on how fast you're going. Obviously, the greater the initial speed at the time of the "mistake," the higher the RPMs will be at the lower gear, and the greater the slowing effect is on your speed. If you release the clutch gradually, you'll notice that something is wrong and that will give you time to shift into the correct gear. If you're bad with the clutch, the car will jerk to a sudden lower speed, and your motor will suffer.

I use downshifting to slow down gradually. If I'm slowing to a halt, I shift from 5th to 2nd, or 4th to 2nd. The key is smooth clutch action.

Id listen to him. he sounds like he know what he is talking about. manuals are easy. wouldnt want anything else but

 

[Banana]

Originally posted by: skateallday

Originally posted by: 1YellowPeril
There's no safety mechanism, except maybe for preventing you into shifting into first. The effect of downshifting will depending on how fast you're going. Obviously, the greater the initial speed at the time of the "mistake," the higher the RPMs will be at the lower gear, and the greater the slowing effect is on your speed. If you release the clutch gradually, you'll notice that something is wrong and that will give you time to shift into the correct gear. If you're bad with the clutch, the car will jerk to a sudden lower speed, and your motor will suffer.

I use downshifting to slow down gradually. If I'm slowing to a halt, I shift from 5th to 2nd, or 4th to 2nd. The key is smooth clutch action.

Id listen to him. he sounds like he know what he is talking about. manuals are easy. wouldnt want anything else but

Wrong==I don't know what I'm talking about. Listen to the gear heads instead.

 

[LOLyourFace]

dispel these myths please:

true or false?
1. fully depressing clutch in 1st gear for prolonged time (1min+) to take off faster is during a red light bad for the car rather than leaving it in neutral & brake.

err, that's all i can think of now.. is this true or false?

 

[Demon-Xanth]

It causes more wear to the throwout bearing when you hold the clutch in. IMO, it's better to stick it in neutral.

 

[LOLyourFace]

Originally posted by: Demon-Xanth
It causes more wear to the throwout bearing when you hold the clutch in. IMO, it's better to stick it in neutral.

u sure? the clutch is fully depressed. not partially depressed to 'ride the clutch'

 

[Banana]

Originally posted by: LOLyourFace
dispel these myths please:

true or false?
1. fully depressing clutch in 1st gear for prolonged time (1min+) to take off faster is during a red light bad for the car rather than leaving it in neutral & brake.

True. And please don't pop the clutch to impress the chicks.