Eaton has been working on automated transmissions for about 40 years, and the going has been slow because there is nothing simple about making a manual gearbox shift itself. Work began with a military contract that funded early development. Out of that project came technology that engineers built on, and continue to.
Early products that Eaton took to market were crude by today’s standards, but still impressive when they worked. The first one I remember was the CEEMAT (for computer-enhanced, electronically managed automated transmission) in the late 1980s. It was tested in concrete mixer trucks, one of which I drove and liked, even if the gear changes were a little rough. I liked it because the gearbox transmitted full power and torque to the rear wheels, and multiple speeds allowed the engine to cruise easily out on the highway. Allisons of the time felt mushy, and with only four ratios, engines ran out of breath much above 50 or 55 mph. But CEEMAT wasn’t on the market long.
In the 1990s came the AutoShift, with better electronics and shifting behavior. It did have a manual clutch for stopping and starting; otherwise the transmission float shifted while the clutch remained engaged. It had some annoying quirks, such as staying in gear when the driver shut off the engine, and he’d then find that he couldn’t restart it. Also, you had to be sure to fully depress the clutch pedal or it wouldn’t change from Neutral to Drive or Reverse. Even so, the AutoShift took a lot of work out of driving, and if you didn’t like the way it shifted you could use the selector to choose the shift points yourself.
UltraShifts without the clutch pedal—so-called “two-pedal” transmissions—came soon after and were more successful, if not entirely smooth or completely reliable. A centrifugal clutch made some starts a bit dicey. And electrical shorts somewhere on the chassis could migrate to the transmission’s controls and bollix it up to where the gearbox stopped shifting correctly, or at all. Managers at one early adopting over-the-road fleet found they had to have mechanics capable of tracing down and fixing shorts at every shop in the system so these trucks could be repaired and sent back out.
Further electronic and mechanical advances resulted in the UltraShift Plus series that Eaton continues to sell. It has a normal dry clutch that’s more positive in engaging, and while today’s products are not perfect (what is?), they are so refined and well behaved that it’s difficult to put them in the same class as their predecessors. And Eaton engineers have applied automation to models familiar to users of construction trucks: the venerable 8LL and 9LL, plus an 18-speed set up for severe service. There’s also an Advantage series for on-highway trucks that use lighter-weight gearboxes tuned to work with specific diesels.
All of these not only shift themselves but also do it correctly more often than an average driver can, and don’t tire out at the end of a long day like he will. Maybe best of all, they’re affordable, with automated models costing about $2,000 to $6,000 more than a comparable manual, depending on the tranny model and the truck builder.
The latest in the story of Eaton’s progress are two new low-speed maneuverability features for its vocational and highway automated transmissions, which representatives demonstrated late last fall at its proving grounds near Marshall, Mich. The features include special clutch engagement called “Blended Pedal” and “Urge to Move.” These allow precise movement of a truck to properly place loads of aggregates or concrete, for example. The new features are available with UltraShift Plus and Advantage transmissions, and work thusly:
- Blended Pedal provides gradual or quick clutch engagement depending on the accelerator’s position. A light foot sends the clutch face partially against the flywheel, and releasing the accelerator disengages it. Stomping on the accelerator engages it fully and quickly. This works when the transmission is in Low or Manual modes, and in Reverse in some trucks. It is akin to a driver using the clutch pedal of a manual transmission to slip the clutch to move the truck very slowly and for very short distances, or to abruptly engage the clutch to get out of mud or soft ground.
- Urge to Move is enabled in Drive, Manual, Low or Reverse. The driver releases the brake pedal, and the clutch smoothly engages at engine-idle speed (about 700 rpm), moving the truck forward or rearward and keeping it moving as long as the service brakes are off. The power train then is in “creep” mode, or the driver can push the accelerator to gain speed.
I drove several trucks whose transmissions were programmed with these features and tried them under various conditions. With Blended Pedal, I stopped and started dump trucks and a mixer chassis on level ground, then on steep grades, easing on and off the accelerator to simulate what a guy would do while maneuvering a vehicle to properly place a load of gravel or concrete. I could feel the clutch nicely engage and disengage, and engage suddenly but smoothly if I jammed on the foot feed. No matter what you’re doing with an Eaton automated product (or those of competitors), clutch engagement is almost always consistently smooth and proper.
Urge to Move was a little more interesting: With the transmission in gear, I took my foot off the brake pedal and felt the clutch engage and the truck began moving at engine idle speed. The tranny will try starting normally, in a higher gear (4th was common with an LL type), but will change to a lower gear if it finds the ratio reduction is not sufficient. Or, a driver can choose one himself. All the diesels were heavy-duty models with strong torque at clutch engagement, and electronic controls on the engines fed enough fuel to keep the trucks rolling as long as I wanted. If I got on the go-pedal, the truck accelerated and upshifted as needed.
Most impressive was a heavy-haul tractor with an 18-speed pulling a loaded multi-axle trailer (gross weight was 125,000 pounds) on a 15-percent upgrade. Urge to Move started it repeatedly and although the front end hopped a little as the clutch engaged, the rig started up strongly. There was one hiccup: On the first try the engine killed and had to be restarted. The demo driver said the 16-liter diesel had been acting up.
Of course, a driver can put a manual tranny in Low (or one of the Low-Low gears), ease off the clutch pedal, and the rig will begin to move on level ground. On a hill, it can still be done. But it takes a steady foot on the accelerator to keep it moving without surging. And upshifting competently on an upgrade can be tricky. A guy with some experience can do this, but a novice will have trouble, and while he’s learning he can burn the clutch or break a U-joint or something worse. Put him in a truck with an UltraShift Plus with these features, explain how they work, and with care he can do it correctly the first time.
In my opinion, though, some driver training is needed. Driving an automated transmission with an automatically actuated clutch (Eaton’s or anybody else’s) requires the driver to understand what a clutch is (some young people might not know) and how it should be respected. An UltraShift Plus will protect the gearbox, the clutch and the engine (it will upshift to avoid over-revving while accelerating on a downgrade, for example). But to get the most out of it—including these two new features from Eaton—a driver must know they’re there and how to engage them.
YouTube has some videos by Eaton and some by regular guys sharing tips and sometimes complaints. Eaton will send technical reps to help. Any boss who doesn’t want to bother with any of this can either stay with straight manuals or buy full automatics from Allison (or Caterpillar on a Cat Truck), which will be more forgiving. But the price premium will be more dear.
Blended Pedal and Urge to Move can be programmed into electronic controls of Eaton’s Vocational Construction Series (VCS) 8LL 10-speed, Vocational Multipurpose Series (VMS) 9LL 11-speed, and 18-speed Multipurpose Extreme Performance (MEP) models, Eaton people said. They’re also available in highway versions of the UltraShift Plus and Advantage series. Of course they’re available on new transmissions, but can be applied to many existing models, too. Eaton reps will program the transmissions’ electronic controls to enable the features, often at no charge. So can owners, with the correct software on laptops. Or dealers will do it for a fee.