Manual vs Automatic Transmission: Which Is Easier to Learn?

Unless you're using the jakes going down a grade, driving on icy roads, or any other time you need to control when shifts happen and/or when power goes or doesn't go to the drive wheels.

Kinda hard to hit the clutch in order to stop a drive-wheel power skid when there is no clutch.

 

I am driving my first ever auto truck and found that in the mountains I often manually shift because it likes to lug the crap out of the engine on upgrades and heat up the water temp to levels that make me uncomfortable. Downhill with a heavy load it needs help to keep from overspeeding.

Overall I like it and feel I am being spoiled. With the car transmission and e-logs this doesn't even feel like trucking. I am still a rookie compared to you vets that were out here since the 70's but even I started out to running to the west coast with a 13 speed and paper in a truck that did 85 mph. When I got into it only a couple megas had e-logs.

I never though I'd say this but OTR and trucking in general might be an endangered profession seeing how rapidly the automated truck technology is expanding.

 

I have the Auto DT-12 and find myself running it in Manual mode most of the time. The thing likes to jake hard down bunnyhill downslopes and gives away too much free power that could be used to climb the next upslope. So in that situation I use Manual. Other times, say in Auto mode I look down and in cruise, it is shedding speed off approaching a slight uphill grade in Ecoast and the truck behind me gets on the CB cussing me out for slowing down. Then they try to pass and the auto begins to go down the hill picking up speed. Cussed out again for the pass block that was not my intention. Worst one is in auto mode and trying to pass someone say in 70 cruise control and it decides to go into Ecoast and loses a bunch of speed and can't pass because we lost all our momentum. Have to touch brakes and tuck back behind slower truck and try again with foot on pedal next time.

Bottom line, learn on a manual and drive it for a year before you get into a auto because you won't even know what you don't know if you don't.

 

Set your cruise at a lower speed. It'll keep your speed down. I use cruise on all the downgrades and I never have issues: Grapevine, Cabbage. You just have to know how the auto works with the Jakes and cruise.
As far as a clutch for skidding, flip it in neutral.

 

The transmission week shift when it needs to, not when the driver thinks it needs to be shifted. These new DT12s are supposed to go down to 1000 rpm or less; that's where all the torque is.

As far as downhill, I can set my cruise at 30 mph (the lowest speed for my ECM configuration) on the Grapevine which is 35 mph truck speed and I will hold at 33-35 mph all the way down. I sometimes have to hit my brakes for traffic, but otherwise the truck does it's job.

I should mention that I have the predictive cruise on my truck so it knows the terrain I'm in and adjusts accordingly.

 

If the truck knows the terrain etc. Then the driver is no point being present. Let the truck drive down there.

One of you spoke up about bunny slopes where the jake kicks you in the nuts knocking everything down and that was a issue. Then you would have the take off and overspeed on the downgrade because it does not know any better, it wants to GO. 10% down is go enough. It does not need to be adding power.

Some of you are sprouting very low lug numbers that I would not allow a engine to get down before kicking her down a gear. If you are trying to "Get under" your engine by seeing it slow that much you are not going to be able to get going without a downshift which might even need to downshift twice or skip one on the way to the next one down to put the engine back into it's power spot.

Finally one of you talked about kicking her into nuetral to break a power skid. IMHO those are pretty rare. You are now in N what do you do with the tail of the tiger fixing to claw you now? Im assuming ice here... You need some power to keep it settled and that 5th wheel leaning on it so to speak, I don't know how else to describe it. That trailer and it's load would be to use a kids cartoon from thomas's troublesome trucks, shoving the engine where they can create trouble.

Im not trying to pick trouble it is enough already to have a discussion between autos and manuals. I always say use a manual first until you get good at it. That truck behaves a certain way on manual you will not often get out of auto.

No matter how steep or what trouble it's fixing to pull on you there is a gear for that somewhere on the manual tree.

 

The Paddle Shift in Manual mode on the DT12 is pretty tiring also.

 

Here is the scenario--

Cruising along at 62 and we come down a little tiny hill and gonna be going back up a tiny hill before the road levels out. Now normally in a manual, you'd just let it gain speed up to 70 or so and use that free power to help get back up the next little hill.


With the auto, it downshifts from 12th to 10th and aggressively jake brakes to about 50 miles per hour then has to work its tail off to get back up the hill.

In that case I have to press on the go pedal and paddle upshift but it is already too late, cannot manually upshift fast enough. Lose too much speed.


So I see the downhill coming up and either already in Manual mode or set it for manual mode just before going down, this locks it in 12th and we can gain speed and use it to get up the other side.

Yeah, sure my left foot doesn't have to do any work any more but I am preoccupied with constantly monitoring if it is in manual or auto mode, trying to override and outsmart the transmission to get max efficiency.

 

@scottied67 . I'll attempt to address some of the concerns you mentioned in this video.
-1st off, the very 1st time you go down a particular steep grade, it's kinda of a guessing game. You'll have to do it a couple of times to get it just right. Then it'll come to you automatically in the future. I'm sure almost all of us can sound off what gear we would take certain hills at from memory. This is no different.
-I would have set my cruise for approx 15 mph below the desired maximum speed. That should do the trick. If it doesn't, I always have the manual Jake lever to throw it in #3 if needed. If I needed to actually apply brakes, then the next time I would have set it at 20 mph below desired speed. Again, a learning process.
-You mentioned several times in the video that when the truck exceeds 2 mph over set speed, the James are supposed to kick in. That is not hire our ECMs are set up. This is an ongoing debate between our shop and Freightliner because of all the excessive speed reports they are getting. That's another discussion..... The Jakes are kicking in on our trucks at approx 7 mph over set speed.(at least on my truck) I have given those videos to our shop so Freightliner and JCT can figure out why. They have done SOME adjustments to some of the trucks already (not mine) a couple of months ago. Not sure of the current status of things as I haven't been there during business hours since February.
-You also have the ability to up shift or down shift in auto mode with the flick of a finger. No need to go into full manual. But if cruise is on, be ready for the truck to go back into what it wants to in a few seconds.
-Freightliner provided us with a video explaining (or trying to) the downhill operation. If you look in the owner's manual, you will see that it tells you that going up to 2300 rpms is ok. The video states that it's ok to go up to 2500 rpm. Now, I would never go that high personally; that's just nucking futz.

To address some comments from others:
This is new technology. With that in mind, the "old traditional ways" and the ways most of us that have been driving over a decade were taught, go completely against the way the technology is set up these days.
Yes, years ago, it was the norm to go up a hill with max rpm before you up shift as that was were ask the torque was. Not these days. These autos will up shift sooner to keep those rpms lower to keep you in the "torque band" That's why rpm speeds of 900-1100 rpms are ok and it's not lugging the engine like we were taught.
You have to remember that today's technology is focused on fuel efficiency, not performance. They try to get a good mix of both, but it seems that it leans more towards the efficiency side.

One issue I have come across is some drivers that are coming up on a steep downgrade are still accelerating or trying to get to the speed limit before they start going down. WHY??? It makes no sense at all knowing you're gonna have to slow down considerably on that downgrade to keep accelerating just to hit brakes that much harder.

Example: Driver climbing hill at 40 mph. Gets toward top, accelerates to 60 mph as it levels off before descending a truck speed zone of 45 mph on the downgrade. Then hits brakes to slow back down to 45 mph.

What did that accomplish? Not only did you waste fuel, but you just heated up your brakes unnecessarily and possibly created a brake fade that may make the difference in an emergency situation further along that downhill. Why not maintain speed of 40 mph and then go down hill, possibly never having to touch brakes all the way down.

It's simple impatience. Every one I'd always in a hurry, ###### every one our everything else.

Back on topic.....This new technology in the auto DT12 and it's integrated satellite GPS terrain mapping is asking for drivers to put a tremendous account of faith in their vehicle. I admit....I was hesitant at 1st. I took that leap of faith and utilize the full features of the truck and allow it to be as much of an automatic as possible. Of course the driver must remain aware and ready to intervene in an emergency, but trust the technology.

New technology is not a bad thing, it's just different and human nature tends to resist change, even if it's for the best.

Technology is advancing at a rate that is so fast, old farts like me have a tough time keeping up, but I'm game to try. It's not all bad, I mean when I was a kid, I was the remote control. "Hey, get up and put it on the other channel." Now there are more than just 3 stations on t.v.and I can tune in to any of 500+ channels and never get my fat butt out of the chair. See? Technology good.....living in the past bad.

Too many drivers are stuck in their ways and think that newer things can't possibly be better. That's a very closed minded way to view this industry. You have to be open to changes. Of course not every thing new is better, but unless YOU, yourself, actually try it and don't just simply take someone else's opinion, don't be so harsh and quick to slam it down. And yes, that applies to my post too.

 

People are over thinking the autoshift or DT-12 anyway. One thing drivers need to understand is when every you turn the engine brake on it will stay on and keep slowing you down. But here's the difference. If you turn on stage 3 you will get maximum braking the engine and transmission can give you working together. That's the BIG difference because the engine and transmission will ALWAYS keep RPMs in the 1800-2300 rang.

Your telling the truck you need maximum engine brake. It will give you maximum engine brake for as long as you ask for it. So it will keep downshifting and slowing truck from 70mph all the way down to like 15mpg in the 1800-2300 RPM rang because you are tell the truck you want maximum engine brake.

Stage 1 and stage 2 keep engine rpm in 1300-1800 RPMs. So when your going downhill and you turn on engine brake look and watch your RPMs.

In automatic mode downshift and dring up the engine RPMs to 2000 and turn on stage 3. Now as the truck slows and the RPMs reach 1800(that's the shift point to drop a gear) you have 2 options. If you want to go slower let the transmission downshift and keep slowing down. Option 2 is at 1850rpm flip the switch to stage two engine brake and keep rolling down the hill.
Then if the truck speeds up you let the RPMs climb back up to say 2200 and flip stage 3 back on. The transmission won't downshift because stage 3 is 1800-2400 RPMs.

Then let truck slow down to 1850 RPMs and if you flip the switch to stage 2 it won't downshift. You have to turn off stage 3 before the shift point of 1800 RPMs otherwise it will keep slowing truck down in stage 3 all they down to 15MPH