It just crossed my mind. With cars you get more milage if you have a manual. Now they have CVT that was claimed to be very efficient, not sure when compared with manual transmissions though.

Since trucks have automatic transmission as well, are they less efficient to drive compared to manual transmission? Maintenance? etc....

this is nothing really, just curious to know.

It's been explained to me that auto-shifts (which are completely different than automatic transmissions, mechanically speaking) are in fact more fuel efficient because the computer that synchronizes the transmission does so perfectly every time. Whereas with a manual shift, even the most seasoned professional could miss a gear and thus require the RPMs to change once again, thusly burning more fuel.

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Keep that diesel burnin' and those tires turnin', but get there safe to keep on earnin'!!

It's too bad that we all (myself included) can't remember our own short comings at the exact moment a fellow man or woman is having one of their own.

In cars, manuals used to be more efficient, but not anymore. Old autos used to take as much as 8 hp just to spin the transmission, not they are at less than 1 hp. They used to shifted based on RPM and vacuum, not they are controled by computers. Now adays, autos are usually listed as getting 1 or more mpg than manuals in the same cars and light trucks. Most of this can be attributed to human variances in driving.

Truck transmissions may not be there yet. If not, it won't be long, although I'd have questions about the reliability.

Interstate Distributors runs all automatics. We have 2 of their trucks at the school and both have close to 1 million miles on them and they drive great! So far I love the auto shifters.

i actually own one,the trans itself is strong but the electronics and other controller parts are still in their infancy.problems will start becoming likely around 600-650K miles,mine was the TCU and the range valve six months later.it still ain't 100% right but freightliner mechanics ain't all there either.i prefer a 13 speed but they can fail in as little as 300K miles so each has their own ups and downs.the 10 speed is most likely the most reliable since it seems to be used by most companies.

lol....well Ill toss in my 2 cents. I don't drive truck (yet)..but for the last few years, have been driving Penske trucks when we move. Last month was my third time and I again used a 26 foot truck. With Penske, their 24 and 26 footers are diesels. They have automatics in them and I think some of them (at least the ones I drove) have an econo-mode which shifts at a lower rp for when you are out on the road. I know the truck is shorter and lighter than trac trailers....but it still gets up in speed pretty quick. I can't compare it to a stick as I havent driven a large truck with a stick....but I like the autos....pretty shnazzy.

automotive auto trannys use 15-20% of their operational TORQUE not horsepower to rotate the hydro assembly.

direct drive manuals use far less - but human err - and inconsistant rpm ranges kind of even out fuel economy


the mileage difference - all things being equal - between two identical trucks - one with auto - one with experienced driver is less than .3 miles per gallon

but that mileage difference at the end of the year could be as much as 9K$ in fuel.


back in the early 1970's they came out with a real automatic for trucks - looked like a GIANT TH350 or TH400 - HUGE it held 12 gallong of fluid - pluse a cooler the size of a turbo heat exchanger...


they did not catch on - they added 500+ lbs to the rig - and they were not reliable.


(eaton fuller service notes - 2002)

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TEAMSTERS LOCAL 100


Faster than a 60 MPH bullet....

I finally got to drive an auto shift for the first time in my 16 yr career, it was in an international DC what model 4200 4300 i ??? not sure, any how when I backed under the trailer I was using I almost drove right through it, there is a slight lag or delay which You seem to have to time right when Hooking up, when I got it on the road, it was pretty nice pulled well, but I found my self throwing my left leg and foot to the floor when comming to a stop, which fo some reason made my stopping ill timed, after a few hours this subsided, but I will say be careful if You have driven Mannys all your life in a CMV. It always had a lag though when starting out almost like a stall converter in a drag or hot rod, this may not be right and something may need to be fixed, bit I never drove it since and really don't care too, Although the company I am going to work for soon runs pretty new equiptment 08 petes and 06-07 Liners. I am wondering what kind of tranny theese will have, if they are autos I will be a little dissapointed but I guess I have no choice if thats whats in there..
SAFETY FIRST!!!

Well, the biggest truck i have driven so far is a Penske 26 footer with a car hauler so Im not in the big leagues as far as comparing tractors to tractors and such with manuals and automatics.

However, the 26footers from Penske come with diesels standard. They were Internationals with Cummons engines and automatic trannies.

Now that it has been mentioned, I remember there is a lag of a second or so from the time you press the gas until you feel the reaction. At stop lights, I would press on the pedal when the car 2-3 cars in front of me would start moving.

They are nifty, no need to worry about shifting, and the ones I have driven came with an econo mode which lowered the rpms for shifting when driving on the highway. Even under load, it performed with no issues and I think it gets off the line rather quick compared to manuals because there is no shifting.

Of course, I don't know how many gears it had either....five or six? Not sure how many gears are on the big rigs with autos.

I have drove only 26 footers the one I got my "b" on was a GMC with a 6 speed I loved it. I went to work a company that used a F650 with an auto it was hell getting on to I75 in clarkston. Give me a manual tranny any day over an auto (unless its with my kids)

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