This may be an old question: is it beneficial to shift into neutral while coming to a stop in an automatic transmission? But, my new Ford Fiesta has a PowerShift 6-speed transmission that behaves differently from a standard automatic. According to Ford, it’s “like two 3-speed manual transmissions put together, with the dual clutch and shifting components controlled electronically.”
Since the PowerShift is really a computer-controlled manual transmission (without a fluid torque converter), it’s actually in neutral when I’m stopped and the shifter is in Drive position. I can feel it disengage as I come to a stop. However if I try coasting to a stop uphill, the engine still pulls the car upward at low speed without my foot on the accelerator. So the computer has to judge when to activate the clutch. The issue is, I tend to apply the brakes lighter than average and decrease speed at a slower rate to come to a stop. So I think I might be confusing the computer, working against the engine before it wants to disengage the clutch, whereas most people would come to a stop more abruptly and the shifting action would have no problem. This is why I shift into neutral early in my slow-down phase, so the engine doesn’t have a chance of pushing the brakes.
Does anyone out there have a car with such a transmission, and how does it affect the discussion on shifting into neutral?
My SO has a car with a DCT. They’re odd little beasts. We experience similar computer confusion to yours. Hers especially dislikes changing throttle input in 2nd gear. If you’re flooring it when it shifts to second, it wants you to keep flooring it. If you let off the gas, it freaks out a little bit.
The main issue I have with DCTs in “cheap” cars (as opposed to the Porsches, etc, in which they are reported to work really well) is that it seems less money was thrown into making them work perfectly at all times, and so situations pop up that the computer doesn’t know how to properly handle.
That said, I would not be shifting into neutral. Leave it in drive. In the first place, it’s often illegal. And it’s unsafe. If some idiot comes barreling up behind you because he doesn’t notice you’re stopping, the extra time it takes to move the lever to drive and for the computer to engage the tranny could be the difference between you getting hit and you getting away from the guy.
I would also brake a little harder. Too-light braking can glaze pads and rotors, which reduces their effectiveness and can, again, lead to a safety concern. You don’t have to be braking like a race car driver or anything, but a good firm stop is better than light braking for a long distance.
I agree with the legal and very minor safety issues pointed out by shadowfax. I’ll also point out that braking very gently for a long time is probably annoying the drivers behind you, so I also vote for braking with medium pressure instead.
THAT dual clutch is one of the worst designs I ever seen. Our shop is full of those, both recalled and with problems. Every single one is backordered and they can’t keep up with demand. They say it’s redesigned but I wouldn’t trust it either way.
Drive it like it’s designed for and don’t be asking for trouble…you’ll probably end up with it anyway.
The OP should be aware that Ken Green is a Ford parts man of many years experience, so if anyone is familiar with the failure rate of that transmission, it would be him.
The OP should allow the transmission to do its own thing, and should also keep his fingers crossed that his unit is not one of the ones that fails.
According to Ford, it's "like two 3-speed manual transmissions put together, with the dual clutch and shifting components controlled electronically."
Just curious, is that true? Literally I mean? There’s actually two separate 3-speed manual transmissions in that arrangement? All of the manual transmission gears and shafts are duplicated? Then the transmission computer just ping-pongs back and forth between the two when a gear change is required?
The malibu we test drove the car actually turned off the engine, 2 batteries, one for the car and one for starting, neutral in that case means nothing. My assumption would be no user intervention needed. Or my favorite computer pic on screensaver for kiosk,
“That said, I would not be shifting into neutral. Leave it in drive. In the first place, it’s often illegal.”
In what state is it illegal to shift into neutral, and why? I don’t shift automatics into neutral, but have ridden with people who do. I ALWAYS wait in neutral in manual transmission cars. It seems that sitting at a light with an automatic in neutral would not be any more against the law than sitting still with a manual. I’m also curious how any officer could see a violation and enforce such a law.
Is this one of those things that are supposedly common knowledge which are not true? A retired police officer friend of mine told me that EVERYONE KNOWS it’s illegal to drive a car without a hood, or to drive barefooted. In truth, neither of those “laws” are on the books. The barefoot thing kind of makes sense as one could definitely brake harder with a shoe on, but it’s not illegal here. In fact a friend of mine had an accident while driving barefoot. While an investigating officer noticed his hot work boots were on the passenger side floor, she only commented that barefoot driving was not a good idea. He didn’t get a ticket for it, only running a stop sign.
Driving while stupid is apparently not a crime either. I see it everyday, but I digress, even more.
@GeorgeSanJose, it really is two subsets of manual transmission mechanisms in one box. Both subsets are always in gear. While the currently used subset is connected to the engine via the clutch, the other subset is engaged in a gear that the computer thinks the car should be in next with the clutch disengaged. Changing gear is a matter of disengaging one clutch and engaging the other.
Having said that, it is simply an automatic transmission with two pedals on the floor. There’s nothing pseudo about it. You can keep both of your hands on the wheel and let it changes gears by itself. AFAIK, if you show up to your California CDL driving exam with an AMT, you get a license restricted to automatic transmission. Anyways, if the engine is pushing the car as it comes to a stop, just as almost any automatic transmission would, ease in slightly on the brake pedal. Shifting any automatic transmission in and out of neutral causes unnecessary wear on the mechanism
BTW, over here in Hong Kong and in mainland China, where automatic transmissions show up much later than in the States, old school driving instructors still teaches their students to shift an automatic transmission to neutral when stopping.
Continuing with MG’s hijack, I also put the transmission in neutral when I see that I will be stopped at a long light or traffic jam. And I will shut off the motor if it will be a very long time.
Re slowing down, I tend to slow down gradually for red lights… There is no real disadvantage that I know of (aside from the glazing the pads bit, and I question that) and plenty of advantages such as fuel savings.
S 1216. Coasting prohibited. The driver of any motor vehicle when
traveling upon a down grade shall not coast with the gears of such
vehicle in neutral, nor with the clutch disengaged.
If you put it in neutral when you’re already stopped, then it’s probably legally fine. If you put it in neutral before you stop and the road is not perfectly flat or uphill, you’re breaking the law in many jurisdictions.
My brother-in-law in the state of Vera Cruz drove all day every day, for 35 years, in his job of inspecting sugar cane. He decreed who got to ship their cane to the factory, and when. All day long. Speed bumps. Rocks. Mountain roads Shifting; shifting; shifting. Hundreds of times a day. For years with an old Beetle, a few years with a small car called Chevy. His legs should have been bigger than Arnold’s arms!
When he retired he got a US made Nissan with an automatic transmission. He shifts that thing by hand. Starts in 1; moves it up to 2; then moves it up to D. And, downshifts when coming to a halt.
He simply can’t change after a couple million miles shifting a manual transmission. I understand so I simply gnash my teeth and don’t say a word.
I sometimes pull my shoes off on long highway runs. Wards off drowsiness.
Another eccentric driving habit: when I was little a family friend drove with one (right) hand on the steering wheel.
The catch was he’d have his hand at 11 o’clock and his elbow on the wheel at 3 o’clock.
