Automatic or Manual Truck Transmission?

Did you know that it’s possible for an untrained person to crawl into an 18-wheeler and take off down the road? They could even do it if they’ve never driven a car with a stick shift. Granted, this brave soul might run every car off the road because of the raw size of the thing. And of course, it’s as illegal as a trunk-load of dead bodies, but it IS physically possible. How, you say?

Some of the largest trucking companies in the US have entire fleets of trucks equipped with automatic transmissions. The debate between automatic versus manual is a big one among drivers. It’s really not that big of a deal, but you could never tell that by asking a driver which type they prefer. Drivers seem to either love automatics or they hate them with the hatred of a thousand Hitlers.

One argument I hear from drivers is that trucks with automatic transmissions allow too many untrained drivers into the industry. There is some truth to that. After all, every minute a student spends learning to shift gears, they’re also getting actual drive time behind the wheel. If you take out the process of learning to shift, you can be in and out of a truck driving school lickety-split. You know, they’re absolutely right about this one. Although that’s really a philosophical argument, not a technical reason to hate automatics.

If you ask most experienced drivers why they prefer a manual tranny over an automatic, 9 out of 10 would say, “Because I like to have complete control of when I shift. I ain’t leaving that up to a @!$#ing computer.”  These drivers are ignorant. Now that’s not a slight to their overall intelligence, I’m just saying that they really should know what they’re talking about before they start barfing out opinions on subjects that they know very little about. When I find a driver who really hates automatics, I find that most have never even driven one.

Now I may be ignorant on a lot of subjects (The Evil Overlord’s taste in men comes to mind) , but this isn’t one of them. I’ve driven both types of transmissions so I can tell you that as far as I can tell, there’s only one thing a manual transmission can do that an automatic can’t, and that has to do with the engine speed and the engine brake, or “Jake” brake.

If you let off the accelerator in a vehicle with a manual transmission, the engine will start slowing you down. You may have experienced that in your friend’s car. You know, the one who really liked the Fast and Furious movies. Same goes in a big rig. Only if it has its Jake brake turned on, it’ll kick on immediately too. Not so in an automatic.

If you’re in an automatic, when you let up on the gas pedal it just assumes you want to coast, again, just like your auto-tranny car. If you want the Jake to kick in on an automatic truck, you have to flip a switch, tap the brake pedal or, if it has one, the clutch pedal. So again, there’s perhaps the second point for the manual fans. But honestly, I doubt most automatic-haters even know that. So really other than the whole “inexperienced driver” argument, the only gripe becomes the inability to control shifts.

Maybe I should explain how these transmissions work, in everyday Billy Bob speech, of course. If there’s one thing I ain’t, it’s a mechanic… or an English major (as personified by the use of the word “ain’t”). The manual tranny and clutch in your car or pickup truck is similar to the one found in a big rig, except that it’s waaaay harder to master. Where with a car you can shift at virtually any point that you choose, in a semi you have to shift at certain rpms (revolutions per minute, or how fast the motor is running).

While you’re shifting, you must also double-pump the clutch pedal. Double clutching involves pushing the clutch pedal in half-way, taking the transmission out of gear, quickly getting the engine to the correct rpm, pressing the clutch half-way again, and putting the tranny into the desired gear. To an experienced driver, this all takes place in the blink of an eye. But experienced drivers can also do the shifting without the double clutching. We call this “floating” the gears. The Evil Overlord and I are proud members of this holier-than-thou cult. Actually, most truckers learn to do this within a year or two of getting out of truck driving school.

Now on to that awful, shift-controlling, brainwashing, back-stabbing automatic transmission. It wants to take control of your life and drive you off the nearest bridge. It wants to stall you on a set of railroad tracks. It truly hates you and the very air that you breathe. Not.

The first automatic we drove had an accelerator pedal, a brake pedal, and a clutch pedal. The shifter was a lever on the right side of the steering column. The only time you had to use the clutch pedal was when starting or stopping. Other than that, your left foot could take a nap.

Later on we drove a fully automatic transmission. It looked the same except for one thing; the noticeable lack of a clutch pedal. If you were to look into the floorboard of a truck with a fully automatic clutch, it would look exactly like your station wagon. It’s got a gas pedal and brake pedal. It’s truly fully automatic.

As for the shifter, well a picture is worth a thousand words; 10,000 of my words (I am a bit long-winded).

Naturally, R is for reverse, N is neutral, D is drive, and L stands for low gear. Hold your foot on the brake pedal and select a gear. Simple pimple.

Okay. Now as long as that little arrow points at “auto,” you let the computer shift the truck. When you speed up, it upshifts. When you slow down, it downshifts. When you come to a complete stop, the automatic clutch takes over. The only time it pitches a fit is when the weight of your load changes.

When you have a heavy load, it lets the engine rev more before it shifts. Eventually your trailer is going to be empty, but the computer doesn’t know that. It still waits to shift. It will adjust itself if you wait long enough, but who’s got the patience for that? Heck, I can’t even wait for the toast to pop up by itself. And that’s when you point the little arrow to “manual.”

So here’s where the stubborn old timer’s arguments falls apart. I can retrain my truck to shift by shifting it manually. If you pull this lever toward you (up), it shifts up one gear. Push it down and it downshifts one gear. “Yea, but you can’t skip-shift!” Ah, but you can. Skip shifting is precisely what it sounds like. If you have a light enough load, or you’re going downhill, you can sometimes skip a gear to save some time and effort. The auto shifter lets you do the same thing. Bring your rpms up high enough and quickly pull the handle toward you twice. Well, what do you know, cranky pants? I believe that was a skip shift. You can also downshift two gears at once following the same principles as you would with a manual shifter. Any time you feel like shifting gears for yourself, one little finger flip will do the trick.

There is, however, one time when I completely agree with the stubborn old coots. When I’m getting ready to go down a steep mountain pass, the last thing I want is a computer controlling my shifts. With a flick of the switch from automatic to manual, I’m in complete control. If I left it in automatic, it would assume I’m just speeding up really fast and upshift all the quicker. Bad news on a twisty 7% downgrade.

Although I’ve never had it happen, I’ve heard tales of automatic transmissions that upshifted by themselves. This happens when the motor is revving too high and the computer takes over to save the engine. I’ve also had a manual shift transmission pop out of gear under the same circumstances. If you’re super paranoid about that kind of thing, Low gear should give you some peace of mind. When the automatic transmission is in low gear it cannot shift up, again except to save the motor. Let me put it this way. If it upshifts because you’re revving the engine too high, you’re doing it wrong. Plain and simple. However, if you’re doing it properly it’ll maintain its current gear, whether in automatic or manual mode. No upshifts are allowed, but you can downshift until your little heart is as happy as a dog in a leg-humping contest.

So here’s the way I look at this whole debate. If you want to wear your left knee out by double-pumping a clutch pedal, be my guest. If you’re cool enough to float the gears, well, you just go ahead and busy yourself with a constantly moving gear shifter, especially during rush hour traffic.

Me? I’d rather blow out my left knee with my horrendous golf swing. And you’ll wish you had a healthy set of knees if you’re ever trying to escape the path of my wicked banana slice.

*So what’s your opinion? I know you’ve got one. Automatic or Manual? Tell us all about it by leaving your thoughts in the comment section. And how about giving this post a rating and passing it on to your online friends. Thanks*

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19 Responses to “Automatic or Manual Truck Transmission?”

  1. Truck Drivers News Says:

    Hey Todd, hope the holidays treated you well. Another great post here, a lot of good info to it.

    I guess I am one of the ignorant ones though, but I have driven a few auto shifts, and still do not like them.

    But, the ones I drove were from the Freight-liner factory in NC and most of the time they would not make it past the Freight-liner Dealership just outside of Charlotte. Probably were put together on Friday, or at least that is what I always said when I would break down in one of them.

    It could have been that this was a few years ago, and they were still working the bugs out of them too. But, anyway in a manual I never double clutched one either, so I don’t think I was going to wear my knee out..

    Have a good one and keep up the good postings..


    • Todd McCann Says:

      Hey Jason, hope your Turkey Day was great too.

      I gotta say I was surprised to hear about your troubles with automatic transmissions. The first one I drove was in 1998 and in 4 1/2 years we never had a problem. Our company’s maintenance department said that they were nearly as reliable as a manual tranny. We’ve driven automatics on and off ever since without one little glitch (knock on wood).

      I only met one team who had a problem with automatics. Their truck was in the shop and they weren’t happy about it. Other than that, every driver who has actually driven them, has been ecstatic, even a bit surprised at their reliability. Maybe you had some bad mojo at the time. 🙂 That does suck though.

      Thanks for the comment.

      Sent from my iPhone.

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      • Truck Drivers News Says:


        As I mentioned these were trucks directly from the factory, I hauled and delivered piggy backs for a while. They were “brand new” some with less than a mile on them..We drove them to deliveries, so maybe they used us as testers as well, to get the bugs out of them.

        Anyway glad you have had good luck with them. Be safe, and have a Happy Holidays coming up!

  2. neuLindsay Says:

    Yay! Awesome post! I never knew trucks had automatic transmission or how cool they were. Keep the posts coming!

  3. Pam Court Says:

    This is my favorite trucker blog ever! True story!

    • Todd McCann Says:

      Really folks, Pam is kinda like George Washington. She cannot tell a lie. Then again, she did forget to mention that mine is the ONLY trucking blog she reads. 🙂

  4. heidi@trulyengaging Says:

    I cannot believe I read an entire post on shifting gears automatically or manually on a semi and loved it! And I even learned a few clever cliche’s too! Thanks Todd… say hi to evil overlord for me!

  5. Oz Brau Says:

    We have 5 Smartshift trucks and we love them. It makes any drive a pleasure, no shifting. The only thing is not to forget to push the clutch in for a full stop. I forgot once at a weight scale and iot rocked the house, the State Trooper inside was not happy about it. he he he

    • Todd McCann Says:

      I’ll share in that chuckle with you. Making a trooper grumpy, well, it’s the the little things in life that bring much joy.

      I’ve driven automatics with and without clutch pedals. I too have been brought to a jolting stop by forgetting to mash the clutch pedal. I’ve also rammed my left foot to the floorboard on models lacking the pedal. Either way, you wind up feeling like an idiot.

      Thanks for stopping by and commenting.

  6. kredytowe Says:

    I prefer the sign: “No entry”, to the one that says: “No exit”.

    • Todd McCann Says:

      I’d love to reply to your comment, but I have no idea what you’re talking about. Didn’t see any mention of “no entry” or “no exit” in this blog post. Did you perhaps mean to be commenting on another blog post of mine?

  7. Clyde CLOWER Jr. Says:

    Great idea to put controls next to the wheel. what happened to the windshield wiper control stick? Ha… AUTOMATICS AND DOWNHILL GRADES can quickly ruin your day. New drivers take heed… It will kill you! Glad you mentioned that. I’ve had my moments of “seat grabbing” like everyone else. Manual control is the ONLY way to run down steep grades. Great to see Eaton Fuller has phixed this way overdue/overlooked safety issue. Thanks! Clyde Clower Jr.

    • Todd McCann Says:

      Thanks for the comment, Clyde. It’s always nice to have experienced drivers back up what I say. It helps in fooling people into believing I know what I’m talking about. 😉

  8. Rodger Moir Says:

    Hi Todd,
    I’m in my 28th year of commercial truck driving and am currently driving a Freightliner Columbia fitted with an 18 speed smart shift.
    Most of the time it is fine but when it warms up on a strech of highway driving it will not down shift below 11 gear unless the engine is shut down and time allowed for trans to cool, around 10 to 15 mins.

    Previously I drove a mack Vision with eaton Fuller 18 speed manual with about 87000 kms and no problems.

    Before this a mack Vision with 18 speed eaton auto changer,every 130000 kms the solinoid packed up it locked between gears and twice cost over $1200 to be repaired plus time off the road.

    I drove a near new Scania the spent two weeks having it’s auto trans completly rebuilt because it was made from inadequate materials.

    Previously I drove Mack Fleetline fitted with a 13 speed eaton fuller and had no problems with it.

    I also driven Scania and Volvo manual boxes that require to be cluched everytime with no problems.
    I have a mate that drives a Mack Granit with 10 speed auto and he hates the way it screams it’s mack arse off at low speed and dies in the arse going up a hill.

    So for me a good old 18 speed road ranger any day.
    Cheers Rodger Moir

    • Todd McCann Says:

      Well Rodger, it looks like you’ve had mixed results with automatic transmissios… leaning heavily toward the “they suck” viewpoint. Thanks for sharing your experiences with these auto trannys. It’s always good to hear both sides of the story.

  9. Bhekinkosi Says:

    Thank you so much for this comment of you. I’m a leaner truck driver you have helped me a lot l wish to meet you one day in life

    • Todd McCann Says:

      Glad I provide you with a little help. If I can help you with anything in your learning process, don’t hesitate to ask. Thanks for dropping in on the blog.

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