Q: are automatic transmissions supposed to go into neutral if enough throttle isn't being applied? (engine speed drops to idle*?)

On my way home from work, rain was easing up, lights green I slowed down(from 47km/h to about 35km/h) and make the right turn, halfway through the corner i prepare to straighten up, i ease off the throttle(was still doing 30ish km/h) and in what felt like an eternity (epic slowmo brain) my hands kept counter-steering while my brain was still trying to understand what the hell was happening.at full counter-lock the car stopped rotating and headed towards the sidewalk(little island between the opposing lanes where the stop light is placed). BANG i hit, the car is forced around by the impact and I land with the rear of the car facing up the hill I was approaching. Put the hazards on immediatly, got out and expected the worse, saw no immediate damage so i backed up and drove home at 20km/h with my hazards on, steering wheel now pointing to the left.

Jacked the car up and inspected the damage today(sunday). The inside of the left side rim is bent, the tyre has a gash about an inch under the bend in the rim, tyre still holding air. Metal guard on the transmission sump has a dent, sump itself is unhurt strangely. inspected rod ends and rack ends, no visable damage, I unbolt the steering wheel to take it off and re-adjust it, the splines are jammed. I did eventually get the steering wheel off and readjusted.




EDIT: 91 toyota sera A/T with a 4efe 1.3 engine block swap. ( yes its a downgrade sue me >_> )

Let me teach you a few things

Neutral: disengages all gear trains within the transmission, effectively disconnecting the transmission from the driven roadwheels

In an automatic if it's in Drive the car will still move even if you are applying 0% throttle, this is why you need to hold the brake in to come to a full stop.

The vehicle has a selective modes, if the vehicle is in Drive it will not go to Neutral because not enough throttle was applied. They're two different modes completely.


And 35km/h is roughly 22-23 mph... If you were making a 90 degree turn at that speed on wet surfaces with a FWD, you were asking for it.

i don't mean neutral as in the symbol on the lever. when im cruising at 60km/h for example and take my foot off the gas, the rpms drop to idle and i can rev the engine freely in the rpms under where the 4th or 3rd gear was last(using 1-5% of the pedal movement), if i go over those rpms i feel a sudden jerk forwards similar to releasing the clutch pedal on a manual vehicle suddenly. and i didn't literally mean 90 degrees...*opens paint for the first time in ages*



red line is my trajectory, blue arrow is where Ii release the throttle/where the rear end lets go green arrow is where I hit, end of red line is where the car ends up and now im facing the opposite direction (impact at green arrow flings car around).

When going faster and releasing throttle auto transmission will engage clutch or go into neutral, i don't know, but engine speed drops to idle, until you accelerate again. Autos are shitttiest shit ever made in earth, it only causes accidents and makes people dumb.

Quote from KiRmelius :

When going faster and releasing throttle auto transmission will engage clutch or go into neutral, i don't know, but engine speed drops to idle, until you accelerate again. Autos are shitttiest shit ever made in earth, it only causes accidents and makes people dumb.

An automatic gearbox doesn't have a clutch, it has a torque converter. At 0% throttle (idle) and car stationary with "Drive" ("D") selected, it will go a lil' bit forward.
When going at a speed of (for example) 10MPH a gear is fully engaged. When going faster, it will select the best gear for your speed. If you release the throttle, it will engage top gear, i.e. for a 4-speed transmission it will engage 4th, for a 5-speed it will engage 5th etc.

A car in neutral is completely free. A car in the highest gear has still some engine breaking, even if REALLY just a little bit.

The only way for ANY car to go into neutral is... putting the stick/selector into neutral. NO car, even the automatic ones, will EVER go to neutral if you don't want it to. (Of course, except for a gearbox problem).

my car has 4 speeds...at 80km/h in 4th if i release the pedal it will drop to idle. Automatic transmissions do not have a clutch, they have clutches.

It depends if your transmission has a torque converter clutch or not, and whether it's functioning properly. Most automatic transmissions, at least electronically controlled modern ones, have a torque converter clutch. At higher speeds, or sometimes just in higher gears, the torque converter will be locked so it's spinning at a 1:1 ratio so you get better fuel economy. If it doesn't have one, then the RPM will decrease when you let off the throttle, though i don't think it should quite return all the way to idle even if you have no torque converter clutch, but it will decrease substantially when you let off the throttle.

Also, some automatic transmissions will go into neutral under heavy braking, but that's not really relevant.

what happens when your revs drop to idle and then you push the throttle - does it rev up or chokes a bit and gears down?

it revs freely until I reach the rpm that corresponds to the 4th/overdrive gear for the current speed I'm at.

revs up freely..? no way... then it means you are on your speed limit

i fail to see how going into a corner too quickly has anything to do with using an automatic

was a separate question, would you rather I make a separate thread?

2 birds 1 stone.

We run (or used to) the UK Sera Owners Club.

The car, like any other automatic, does tend to put the car in a higher gear on the overrun, and the torque converter frees up too, so effectively you are free wheeling quite a lot more than you would in a manual with a gear and clutch engaged.

However, a Sera shouldn't spin at 30mph. Any modern car would be capable of taking the turn you described at surprisingly high speeds, and understeer would be the first problem, not oversteer.

This of course doesn't hold true if you've modified the car. The Sera, standard, is a horrid boaty car that's massively underpowered, poor brakes and dead steering. If you've lowered it (possibly by fitting a Handling Kit*) then chances are the handling not be as forgiving as standard. If you've also changed the weight distribution of the car, changed anti-roll bars etc, then it's even less likely the handling will be safe.

*Effectively, shorter springs and firmer dampers that actually is meant to lower the car and reduce the boaty feeling, and is not actually intented to improve the handling.

If it's standard, then the problem is entirely the driver being incompetent. If it's modified, then the person who specified the changes is incompetent (and the driver may also be incompetent too).

That's the tristan i know, Fearless and calling people incompetent right out the gate.

:heartbeat

Sorry for (quite) wrong info from me then. I wasn't interested in how autos work, because i hate them. I have driven quite a few, but only because i was forced. I just thought it works like that.




Feel the power of Jesus!!

It will be a locking torque converter that locks up like a real clutch when at a designated rpm. It will stay locked until roughly 1000rpm (on most iv driven) away from idle then break the lock and pretty much put foot on clutch until the revs come up again for it to drive the box...

Older torque converters didnt lock and would let engine idle as soon as u lift off the gas, Newer ones (80s+) are designed to lock for economy and a bit of engine braking before letting the lock go.

Tristan! <3 . the only thing done to the car is the smaller 4e 1300 block, the car had 4 well worn tyres on it and I only had enough money to buy 2 good tyres ( the car under-steered at 15/20 kmh in the rain, was deathly scary) I put http://www.esalles.cl/images/POTENZA%20GIII.jpg <- those tyres to the front and now the car was safe in the wet ( well it better be, for $505 dollars in tyres :@)

Tristan is right, I am incompetent, in hindsight I should have stayed at work and slept in my car or wait out the rain, regardless of the situation I cannot be certain that i was 100% aware, while i was sideways and counter-steering I felt like an out of body experiance. :S

EDIT: This week has been quite annoying, as I was being extra careful with the car because i'm saving money to buy something else. I think this car can read my mind and my wallet. x)

P.S. @ Tristan, not mph, km/h. so yea I sux? :/

So you only changed the two front tyres to new fresh and grippy ones?

You know that you're asking for oversteer then?

only had enough money for 2 tyres, would you have replaced the rear tyres when the car was under-steering at 15-20km/h if someone spit in the road(mild exaggeration)? >_<. It isn't a race car, I would have to be purposely flogging it to get any kind of intentional ' over-steer imminent' tyre squeal. since I bought new tyres I've driven in the rain multiple times, each time (except for Saturday) the car was 100% spot on and predictable like a tank, no tyre slip ever. 195/65/14 all around.

On a FWD car new tyres should always go on the back. Understeer is a lot safer for most people than Oversteer.

how much are tyres for where you are from? :o I didn't buy the tyres for buying tyres sake. if i had put them on the back it would have been a colossal waste of money and the car would still be undrivable

In the US, the better tires go on the back no matter what because not every boob with a car knows how to control oversteer lol

Quote from roadrash17 :

In the US, the better tires go on the back no matter what because not every boob with a car knows how to control oversteer lol

I always thought it would be smarter to change the fronts first because they'd wear out faster. Unless you're racing that is.

Bin the fronts, rotate the rears to the front, put the new tires on the rear.

I don't drive a FWD, but that is what I would do.

previous owner already rotated the tyres in weird ways, rears were no use at the front.