Auto-shift? Aren't those just for rookies?
Well yes, ...
Regardless of all the rhetoric about fuel economy, they only exist to enable lower training & entry standards for big fleets.
But that's another topic.
Two weeks ago I picked up a 2014 Volvo VNL 780 from where a company driver had left it and went on vacation. Normally they just have me recover abandoned equipment but I decided to haul freight with it during his vacation since he lives close to me & I won't end up having to hitch-hike 600 miles to get home like I normally do.
It is equipped with the D13 engine and the I-shift 12 speed transmission. The fleet's head of maintenance told me these transmissions have been trouble-free so far.
So I decided to ignore my prejudices and evaluate this truck with an open mind.
Here are some observations I made while I drove it around the midwest and the mid-Atlantic states.
It always starts up from a dead stop in first gear, even if empty or bobtail. This makes it slow to get rolling, which normally isn't a problem except for if you are pulling out onto a busy road and can't get out there quickly enough. You will need to wait for longer gaps in traffic. Putting the hammer all the way down from a dead stop is hard on the truck and doesn't accomplish any better acceleration off the line. All it does is race the engine & rock the truck back and forth as power is quickly applied & removed just like if you were to romp on a normal truck in the low range gears.
Because it always wants to be in the highest gear it can be in for your current speed, I caught my speed creeping up in situations when I didn't want it to. Such as parking lots, left hand turns, and tight cloverleaf exit ramps. (Although speeding through truck stops is a common behavior for the type of drivers that auto-shifts were designed for.)
Normally in these situations you put a manual trans in the appropriate gear and govern your speed with the throttle, maintaining just enough RPM that you get an immediate speed reduction when you let off. About 900-1100 RPM. However, when the auto-shift detects that it can save fuel in a higher gear, it will shift, which makes your speed creep up on you. I found myself using the wheel brakes to slow it down when normally with a manual trans I would simply ease off the throttle a bit.
I learned to use manual mode when in parking lots or going through turns or tight curves, especially if I was on a downhill grade.
Other than for low speed situations I just described, I hardly used manual mode at all. This is because in "D" it will skip gears and get you moving faster but in manual mode you must go through every gear sequentially because you only have an "up" and "down" button on the shifter to control it with.
The I-shift comes with a more complicated jake brake controller too. Most trucks have "Off, 1, 2, 3". This one has "Off, Auto, 1, 2, 3, B".
In "Auto" mode, it only works if the cruise control is set, or if your foot is on the brakes. If it is in 1, 2, or 3, it will not work at all if the cruise is set. In the mountains, I had to constantly change back and forth between "A" and "3" or just not use the cruise and keep it in "3". I was using the cruise to climb the hills, and trying to keep the jake on "A" so it'll automatically engage on milder downhills. But on steeper, longer downhill runs, you have to switch it to "3" so you can ride the jake down the hill without having to ride the brakes the whole way down and overheat them. Quite often I ended up turning the windshield wipers on because the lever for the jake is directly in front of the larger lever for the wipers. I find that to be completely unacceptable.
The only nice thing about this truck's jake brake was "B" mode. Past "3", you can pull the lever down momentarily and it will downshift as needed to maintain RPM's between 1500 and 2000 all the way to a stop or until you tap the accelerator.
The shifter console is located on the front right edge of the driver's seat. There is a button you can push when in neutral so you can flip the lever all the way forward to get it out of the way.
On top of the shifter console, behind the shifter is a button labeled "E/P" for Economy and Performance. It will not stay in "Performance" mode very long but it raises the shift points until you reach your intended cruise speed. I thought it might also change the engine's power settings but I didn't see any difference on the turbo boost gauge. I used it on nearly every mountain incline going across I-68 from I-79 to I-70. I ran the truck through there eastbound with 43,000 lbs in the trailer and westbound with only 15,000.
The truck does not climb grades very well. This is mainly due to the fact it has an underpowered engine, compounded by the carrier's choice of ECM settings. In economy mode it will shift into the next higher gear early, even if under heavy load, and lug the engine at 1100 RPMs or less while trying to climb a mountain. This engine is useless below 1200 RPM. In "P" mode it will shift at 1750 if it's pulling hard up a hill, but I noticed that the power begins to fade away at around 1650.
If you put the accelerator all the way down, you can put a little extra pressure on it and it feels like a button being depressed. This is like when you hit the kick-down lever in an older car or pickup with an automatic. It will force a downshift or simply hold out longer before it shifts while in "D" mode.
Nearly everyone I've talked to who has driven auto-shifts say they're great in the hills. I say no, because it's jake brake controller was designed by idiots and requires even more manual intervention to regulate your downhill speed than a truck with a normal jake brake does.
They've also told me they're nice to have when you're in stop & go traffic. Again, I disagree due to the truck wanting to be in the highest gear possible and the speed creeping up, though this can be mitigated with the use of manual mode, (which defeats the purpose of having an automatic).
I've also been told by a couple of drivers that they are nice to have when backing into tight places because the clutch doesn't get hot and start getting grabby and rocking the cab left and right. That is true, however if the pavement isn't in perfect condition, you will need to give it some fuel to get the tires over a little lump or out of a hole and you can end up hitting the dock plate pretty hard. With a manual clutch, the engine is idling. To get more power out of it to overcome uneven pavement, you simply let out a little further on the pedal & the engine governor will compensate for the load. With the auto-shift, in addition to using the right foot to regulate the movement of the truck in those situations when you're used to using the left foot, you have to increase engine RPMs to get more power out of it and once it overcomes the uneven pavement it wants to take off & accelerate.
And I absolutely could not get the truck to hook up to a trailer without slamming hard onto the king pin while trying to gently overcome the friction between the 5th wheel & the bottom of the trailer. I tried to "two-foot" it once and ended up slamming into the king-pin even harder.
So in conclusion, I have to say that no, I do not like the auto-shift. It has it's pro's and con's but I feel the cons outweigh the pro's. I would not drive an auto-shift on a permanent basis. Two weeks is enough.