Filed under: Tech
4-speed automatics on their way out
Transmission supplier Jatco Ltd. believes that by 2015 the 4-speed automatic transmission will be no more. Shigeo Ishida, president of the company, says that newer transmission technologies, like 6-speed automatics and CVTs, will rapidly replace the quartet of cogs that had for some time been a standard in most autos. It is true that 4-speed automatics are fast becoming a criticism of vehicles that still use them. The Corvette made do with a 4-speed auto all the way up to its 2006 model year, for instance, when it was replaced by a six-speed unit. Of course, the Vette had more than enough torque to make up for its lack of gears, as do pickups like GM's new GMT900 trucks that are also debuting with 4-speed automatics.
[Source: Automotive News]
Reader Comments (Page 1 of 2)
Gary 10:24PM (8/07/2006)
While I guess "more is better," I think many times the current ones are misused. I have a 300C with a 5-speed. 4th gear is too close to 5th so that I see little point in it, while there is a pretty wide gap between 3-4, with similar, though not as bad, 1-2 and 2-3. Similarly, if they added a 6th, unless it was between 3rd and 4th, there wouldn't be much benefit.
Amusingly, the models with the V6 only get a 4 speed, while the V8 gets the 5 speed. The V8 puts out more than enough power over a wide enough band that it could get by with 4 or even 3 speeds, while the V6s could really use the extra gear.
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Tommy 10:39PM (8/07/2006)
It's become a symbol of how advanced a vehicle is. Is there any point in Mercedes' 7-speeds compared to a 6-speed or CVT? I have to say, though, that the jump from 4 to 5 speeds is a significant one, especially for 4 cylinder vehicles.
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x23 10:48PM (8/07/2006)
yeah. exactly. sometimes a higher number isn't necessarily better to anyone other than the marketing department.
for instance... electric motors make gobs and gobs of torque... hence why the Tesla makes due with a 2-speed transmission. though i'm sure there are some out there that would insist if the lack of six gears is somehow detrimental to it's performance and is "ancient '50s technology" or some nonsense.
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required 10:54PM (8/07/2006)
Its not for performance or torque reasons. Its for efficiency. a v8 can get by with a 4 or even 3 speed, but it's not going to get more than 15mpg that way. Bring on the CVTs!!
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Asher 10:54PM (8/07/2006)
I wish I could enjoy driving an automatic. It would make car shopping a *whole* lot easier.
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Buckus 11:11PM (8/07/2006)
Why is it the cars that could use a 6 or 7 speed transmission the most are the least likely to get one? Cars with little 1.5L 4-bangers could really use the extra speeds to keep the power on tap, while a Mercedes with a big-ol V-8 could get by on less without a problem.
The answer, of course, is cost, but I'd really like to see a 5 or 6 speed auto start coming on econo-cars first. At least the Honda Civic now comes with a five-speed.
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x23 12:00AM (8/08/2006)
"4. Its not for performance or torque reasons. Its for efficiency. a v8 can get by with a 4 or even 3 speed, but it's not going to get more than 15mpg that way. Bring on the CVTs!!
Posted at 10:54PM on Aug 7th 2006 by required"
you say that as if it is an actual fact. yet looking at the numbers for the 4-speed automatic 2005 Corvette (a V8... obviously.) it was posting 18/26 mileage numbers... 21 combined. 26MPG vs. 15MPG is considerably different.
the addition of the 6-speed in the 2006 model year made the mileage go to 17/27... 21 combined. wow... you're right... those extra 2 speeds made a HUGE difference in mileage... an identical 21MPG combined. thank god for the six speed.
(numbers from the USDOE fueleconomy.gov site)
you do know about the concept of "overdrive" ... right? people can get 30MPG+ numbers in a late '60s V8 Chevelle... just by swapping out the 3-speed for an overdrive transmission. yes. i said 30MPG+.
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jstand6 12:03AM (8/08/2006)
Well, more gears can bring better performance and efficiency. Considering that the upcoming Lexus LS460 will have an eight-speed automatic, those four-speed autos do sound awfully archaic. I think CVTs will be the future once their reliability becomes proven and their cost comes down. Why have four, five, six, or seven gear ratios when you can have an infinite number?
As Gary stated above, some manufacturers really need to learn how to take advantage of these new five-, six-, and seven-speed transmissions, automatic or manual. Take the Solstice and Sky roadsters, for example. They mate an engine that makes most of its power at higher engine speeds with a transmission from a truck, which is geared for engines that make their power at low rpm. And as he stated, why is it that the big engines get the transmissions with more gears, while the small engines are the ones that would really benefit from them?
On the other hand, the consumer needs to learn to accept advanced technology. It is absolutely absurd that manufacturers have to program CVTs to have shift points. It defeats the whole purpose.
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T 12:19AM (8/08/2006)
5 speeds is a definite plus. I have a 4 speed Mustang auto and it has a really high overdrive 4th gear. You can tell its set up for good mileage but it suffers in daily driving because it always goes into 4th as soon as possible. Then you're in too high a gear and it has to shift down again to make up for it. 5 or 6 gears would allow a high cruising overdrive without such a gap between the top two gears.
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jstand6 12:38AM (8/08/2006)
"the addition of the 6-speed in the 2006 model year made the mileage go to 17/27... 21 combined. wow... you're right... those extra 2 speeds made a HUGE difference in mileage... an identical 21MPG combined. thank god for the six speed."
I doubt that Chevy added the 6-speed automatic for fuel economy. The 6-speed enabled the Corvette to provide better performance with no cost to fuel economy.
A few examples:
2005 Mazda3 s (2.3L DOHC L4) 4-spd auto: 24/29 mpg
2006 Mazda3 s (2.3L DOHC L4) 5-spd auto: 25/31 mpg
2005 Mazda6 i (2.3L DOHC L4) 4-spd auto: 23/28 mpg
2006 Mazda6 i (2.3L DOHC L4) 5-spd auto: 24/31 mpg
By switching from 4-spd to 5-spd autos, those two vehicles increased city and highway fuel mileage, and increased performance slightly.
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UH2L 1:14AM (8/08/2006)
More gears is better conceptually, but the resulting higher number of shifts introduce some inefficiency. It also depends on ratios chosen, and shift strategy as to what kind of fuel economy and performance on a vehicle. I remember the 2000 Passat 5 spd auto we had at work and always was annoyed by the 1-2 shift since it seemed to happen so early. More gear speeds means earlier 1-2 shifts, but if the shifts are fast and smooth most people won't notice them.
As for having gear ratios that seem to closely spaced, I think much of this results from the companies observing what speeds we generally drive at. On my 2006 9-3 SC 2.0 T, 4th gear is flexible with the engine all the way from 32 mph all the way up to 48 mph. I wish 5th gear revved a little lower, but 4th is good for almost all my city driving during which I'm at a constant speed so it's a good ratio.
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Glenn 2:11AM (8/08/2006)
I can remember the first (GM SUV) that had a "new" 4 speed; they warned me to turn it off (A3) and I quickly found out that it was awful -- constantly shifting and acting confused. Then I remember how Chrysler had a terrible time with their 4 speeds -- though the Chrysler 4 speeds were way nicer to live with then the more durable GM transmissions -- one of those cases where they were great, but broke every 110,000km.
So I like the idea of more gears, but I have a terrible fear of durability and cost when (and if) they break.
It sounds like the technology has gone up to a point where these new transmissions have extremely long lives -- or I hope that is the case.
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Ultra P 2:48AM (8/08/2006)
This is a good start. Hope it doesn't take much longer for ALL conventional automatic transmissions to be history.
The auto transmission was be the absolute worst automotive invention ever. Fuel-wasting, power-robbing, performance-killing, unerliable, just BAD.
IMO manual gearboxes are still the best for performance and fuel economy when used correctly. For those who don't know how to use a clutch, CVT is way to go. I applaud Nissan (Ghosn) for their commitment to replace all AUTOs with CVTs in their line-up by 2008. Yay!
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Proud Japanese 2:53AM (8/08/2006)
How about learning to drive a manual. You pathetic Americans can't even handle a gearbox. Everywhere else automatics is only for disabled and elderly. Pathetic.
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Howard Kerr 5:37AM (8/08/2006)
Like any other "new" technology, how it's applied...or MISapplied, determines how effective it is.
In the late '60s I drove a SS 396 Chevelle and it managed quite well with just a 2 speed Powerglide. I do, however, have to imagine how much better it would have been with a 4 speed auto...especially one that incorporated an overdrive. Another Chevy product of the late '60s, early '70s, a Vega, was a dog with it's 2 speed Powerglide.
Today, I drive an early '90s Acura Integra. It's 4 speed auto is barely acceptable by "virtue" of it's reluctance to kickdown to any gear lower than 3rd and a feeling that it is sapping all life from an otherwise "zingy" powertrain. With the engine turning about 3,000 rpm at 70 mph, it probably can't use another gear....but for a lower noise level, a 5th gear would be nice.
And by the way proud japanese....I bet many drivers in other countries would embrace automatic transmissions overwhelmingly if manufacturers didn't charge so much for them and car owners would realize that today's automatics are often as fuel efficient as a comparable manual transmission. If manufacturers priced ALL their cars the same, whether they were equipped with a manual or automatic transmission, there would be more automatics sold in NON U.S. countries.
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x23 7:35AM (8/08/2006)
"By switching from 4-spd to 5-spd autos, those two vehicles increased city and highway fuel mileage, and increased performance slightly.
Posted at 12:38AM on Aug 8th 2006 by jstand6"
yes. those are wonderful examples... except those are both 4 cylinder cars. i never stated anywhere that in a torque/displacement-light engine the addition of gears wouldn't be beneficial. it would be.
the post i responded too specifically mentioned V8s and lacking fuel economy numbers using a 4-speed. hence my example using a functionally identical V8 powered car going from a 4-speed to a 6-speed suto... with no real-world change to the mileage numbers.
keys words : V8 / fuel economy
why anyone would get either the 4-speed or 6-speed automatic Corvette in the first place is the biggest mystery.
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Jeff the Baptist 8:28AM (8/08/2006)
"More gears is better conceptually, but the resulting higher number of shifts introduce some inefficiency."
Maybe, but a well-constructed automatic shifts so quickly that you aren't going to lose much power.
My car (a 4-banger) unfortunately has a 4-speed auto. It sucks. If my tranny ever goes, I'm going to see if I can retrofit a 5-speed if at all possible. It doesn't lag horribly with acceleration because it isn't a honda and therefore still has a powerband. But the final drive ratio on the highway stinks, RPMs are at least 1k too high.
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Paul 9:05AM (8/08/2006)
Someone asked why get an auto vette- Legit question- for street use manual is the way to go, but at the track that auto will beat all but the very best drivers anyday.
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davidl340 9:25AM (8/08/2006)
I'd be willing to bet that a modern computer controlled auto is as efficient or more efficient than your average joe trying to shift a manual in day to day driving.
In my experience with drag racing, the more gears is not always better.
Also, there is a point of diminishing returns particularly in modern gasoline engines that have decently wide efficiency rpm ranges, now diesels on the other hand are different.
Ultimately, CVT is where I hope to see us going, I love it in my wife's Prius. These 6-7 speed tranny are getting too expensive and too complicated.
BTW, The comment by Proud Japanese probably comes from a Fast and Furios wanna be whos Honda has as much torque as a 83 Yugo. Wake up, different strokes for different folks, I've had both an auto and manual, autos are just easier.
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MikeW 9:30AM (8/08/2006)
1939 to 2015, I sure hope that 2015 is moved down to 2010.
The 300C has a decade old leftover MB transmission. W5A580, 3.588, 2.186, 1.405, 1, 0.831. The small overdrive ratio is intentional, it is for precise autobahn motoring, MB chose close spacing over ratio coverage 4.3:, that is less than GM's 4L60.
If you think that the jump from 3rd to 4th is big, you are on crack. GM's 5 speed goes from 1.6 to 1. (bigger than 3 speeds and 4 speeds)
Nissan is over 5 years late to the CVT party, and the V6's would be better served by a 6 speed automatic with 6:1 ratio coverage, the current CVT is only 90% of that.
MB 7 speed automatic-6:1, is an upgrade over their 5 speed(4.3:1, and 4.7:1 in 'wide' ratio configuration) and 6 speed automatics (5.3:1). MB now can achieve tall highway gearing with their engines, ie, E550 40mph/1000 in 7th gear for mileage, while having 1st gear short enough for torque converter lockup from a standstill.
The corvette axle ratio was changed from 2.73 to 2.56 when the 6 speed automatic was introduced. Bob Lutz did not want the automatic to be faster than the manaul.
Also MB has two reverse gears in their automatics, perfect for backing up in the winter.
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