Can one manually shift as efficiently as a modern automatic transmission?


#1

I’d rather have a manual transmission and clutch.
Or is automatic transmission, with no clutch to wear out, now better?

Thank you.


#2

What do you mean by “efficiently?” From an energy efficiency standpoint, an auto trans saps more energy from the engine than a manual, so is less energy efficient.

On manuals the clutch will wear out eventually. On autos there are different wear parts that will wear out eventually.

Which is “better?” Depends on whether you prefer apples or oranges.


#3

^ Today, especially with higher fuel prices, I’d rather have a manual transmission.
Curious, is a manual transmission even an option in an Expedition?


#4

Automatic transmissions actually do have clutches. When it shifts from one gear to another, it releases one clutch and engages another.

On manuals, it’s not the gear shifting that wears the clutch so much as it is the starts in first gear. After a gear shift, most of us just release the clutch and there is very little slippage and wear.
Starting, especially up hills and backing up while riding the clutch is what destroys clutches. People who rev the engine and half engage the clutch to hold a hill at a stop light murder clutches.


#5

I dunno but you’ll want to get a good heavy Ace bandage for your clutch leg knee when you start driving a manual. I suppose it depends on the seat position but on that ole Chevy something or other, my knee would snap every time I put the clutch in. A killer in Minneapolis traffic.


#6

HE’S BACK!


#7

Robert, why would you even want a stick shift Expedition?!

Don’t recall seeing any stick shift Tahoes or Yukons, Suburbans, etc., for that matter

Perhaps you’d be one of the few people that would be interested . . . ?


#8
"why would you even want a stick shift Expedition?!"
As a teen I drove a manual Chevrolet 4WD Carryall and got amazing fuel mileage. On some mountain descents I'd place it in Neutral and coast for miles or use the correct gear to maintain speed in compression. Plus, it was so simple. Replaced the transmission oil myself. (Our Expedition transmission does not even have a dipstick.) Have no idea what comes in manual transmissions anymore or if newer automatic transmissions even approach the efficiency of manual transmissions.

#9

“From an energy efficiency standpoint, an auto trans saps more energy from the engine than a manual, so is less energy efficient.”

Years ago, that was true, but it is not necessarily true, at this point.
On some late-model vehicles, the ones with automatics or CVTs are rated for higher MPGs than the ones with a manual trans.


#10
"On some late-model vehicles, the ones with automatics or CVTs are rated for higher MPGs than the ones with a manual transmissions."
Is this due to average drivers who are not as proficient in shifting? I would hope that I could beat any automatic transmission.

In our 1966 Mustang, I had to keep the accelerator depressed to maintain speed in gear.
Let up off the accelerator and the engine slows the car - unless placed in neutral.
Wish I could have compared fuel consumption driving in gear with constantly shifting into neutral and coasting.


#11

@VDC
I hear what you are saying but IMO, they ( autos including CVT) are more efficient in use for a different reason then transfer of energy.

Automatics are less efficient then manual transmissions as far as transfer of energy is concerned (excepting CVT).
And CVTs are not superior to manuals because of better energy transfer as it’s the computer aided gear selection which is infinite for them that gives them the superiority. Allowing the motor to be operated at it’s most efficient rpm for the speed required by the car is the goal of all transmissions. Computers do it so much better then people in practice. Even race car drivers get it.

Nothing is better then direct gear to gear contact of a manual compared to the loss when the torque converter in an auto that is not locked. This along with he energy lost in moving multiple supplementary gearing in the auto makes it less efficient theoretically. But, when in use with it’s multiple gearing, often more then a manual, and computer control which maximizes the shift points along with never being “lazy” or taking a break, the “in use” efficiency can be greater then a manual. Besides, with so few people on the road capable or willing to use a manual properly, they are so tough to find and sell and it begins to make and less sense to own one for many excepting for we control freaks.


#12

With lockup torque converters or dual clutches and 6-8 speeds, many modern ATs are equal, and some better, than MTs mpg-wise. Nothing like a '66 Mustang!

And no, you can’t get any full (or mid) sized SUV with a manual, except a base 4Runner or Xterra, I’d think.


#13

I love a manual tranny. I’ve been driving them for 35 years. The current crop of 6,7 or 8 speed lockup convertor automatics pretty much match manuals for MPG. That’s got to answer the “efficiency” question.


#14

Moot Discussion, Robert.

Who cares ? In the adverse weather conditions that you have indicated are part of your operations, you won’t want a manual transmission. An automatic is better for traction purposes, especially with traction control.

CSA


#15

MPG figures for new cars show the difference between manuals and automatics to be moot.
As VDC pointed out, in the '50s and '60s automatic transmissions were less efficient, but trannys have come a long way.

However, you started the post by saying “I would rather have a manual transmission and a clutch”. So for you, a manual is better.

The only admonishment I’ll make is that since you do emergency responder driving in all sorts of weather, you may want to factor that into your considerations. If you’re rushing blood to a hospital at night in a snowstorm, you might want to have your full focus on the road, and not have an additional chore to do. Even though driving a manual becomes “programmed” into your actions, your situation is unique.


#16

So last week I’m traveling on a cruise ship that has 6 diesel generators, three v12 and three v16 that supplies energy for the ship plus three electric drive motors and four bow thrusters. At full speed of 24 knots it uses 18 metric tons of fuel per hour. Imagine what it would be if the diesel engines were diving the props directly or through gears ? Now this sounds like a lot of fuel but in addition to driving the ship, the fuel is making life fun and easier for a small “town” of 8,000 passengers and crew. Now, the marine industry has long gone away from driving ships directly through gears for many large vessels from the motor to the prop because it’s so efficient using electric drive motors as the diesels can be run for months at a time continuously at it’s most efficient rpm with the speed control done by the electric motors. These diesel motors can be used for a multiple of purposes at the same time through electric generation making the overall efficiency greater. That’s why the CVT is gaining use in cars but electric drive motors may eventually replace them…eliminating the need for any transmission as we know it today in most of our vehicles.

When you consider the partying going on ship boad 24/7 by 6200 passengers, the 16 elevators making everything handicap access over seventeen floors, supplying energy for 25 chefs and co workers to make food in a dozen cafes and restaurants, the mixing of all those drinks, all while bands performed in five entertainment venues and plays were run and shows were put on, the sacrifice of an archaic transmission seems to make sense; and 18 metric tons of fuel an hour…ain’t that shabby.


#17

With respect Dag, you’re comparing apples to oranges. Automotive drivetrains and cruise ship powertrains are as different as two drivetrains can possibly be.

And I feel safe in saying that the designers have developed for the cruise ships the most efficient drivetrains possible for that application. When one is dragging a few hundred thousand tons through water, and paying huge sums of money for the vessel, fuel efficiency matters big time.


#18

@samemountainbike
My point is, cars are becoming more like cruise c ships as we are using the motors with their accessories for multiple purposes. The modern transmission still requires separate power generation and with cars moving towards being self driven, the loss of the transmission is inevitable. Giving up control of the car to a computer and adding accessories means overall efficiency including running air conditioners, entertainment centers and constant selenoid control of a car’s functions, must all be considered more than that efficiency required to just drive the car. . Ergo, loose the transmission and substitute electric selnoids and drive motors. This WILL happen and why manual transmission are getting in the way now of the family auto and restricted to single purpose vehicals like performance cars.

Guess you missed the point and I didn’t do a good enough job in saying that over all efficiency in driving cars is more important then just debating transmission efficiency and which is better, manual or automatic.
Eventually, cars need electric drive motors, like diesel electrics, like ships to realize overall efficiency. The transmission as we know will disappear as the manual is now. It detracts from the overall efficiency of operating a car when driven down the road with all of it’s accessories, safety equipment and management system, the computer, are all being used. EXACTLY AS A CRUISE SHIP DOES. In the cumulative nature of all cars on the road at the same time and all of the polution that occurs, their efficiency matters big time as well…more then any single cruise ship. So, I am not comparing apples to oranges, I’m comparing small apples to big apples. ;=)


#19

Folks often forget that a CVT transmission still needs either a clutch or a torque converter, the CV part just replaces the gears.


#20

There is a lot of bogus info included in the above postings. It seems some posters are not keeping up with technology.
First, manual transmissions are no longer more efficient than a good automatic. That belief goes back to when automatics were three speeds and sticks had four. Any decent automatic today has at least 6 speeds, and many have 7, 8 and 9. GM and Ford are jointly working on a new generation of ten speed autos, soon to be on the market. Not many drivers outside of 18 wheelers are going to want to manually shift a ten speed transmission.
And many of what people today call automatic are not automatics at all. Technically called Dual Clutch Transmissions (DCTs) they are in fact manual gearboxes with a computer controlled clutch (no pedal). No hydraulic torque converter to lose efficiency. If you’ve got flappy paddles behind your steering wheel, you may well have a DCT.
And even the older style automatics on the market don’t rely on that hydraulic link anymore; they typically have lock-ups which provide a direct mechanical drive once the speed has stabilized.
Go check the vehicle mileage ratings at the EPA’s website. The newer automatic transmissions always rater higher MPGs.