Smart, Smooth UltraShift Plus Made for Off-Road

Sept. 28, 2010
shift actuators and load sensing are among Eaton UltraShift Plus's features

Electrically operated clutch opens and closes for most low-range shifts, but stays engaged for many float-shifts in the gearbox's high range. New, more capable electronics, shift actuators and load sensing are among UltraShift Plus's features.
Cat-powered Kenworth T800 dumper was easy to drive on rough trails with its Eaton 11-speed Vocational Multipurpose Series automated mechanical transmission. So was a similar KW with an Allison 4500RDS, but the Eaton should cost less and might be better with fuel.
Dump truck had a paddle-style shift selector, which can be operated by feel; tranny will also work with a keypad type. Either way, it's usually best to put it in D-for-drive and leave it alone.

Eaton Corp. has been working on automated mechanical transmissions for more than 30 years, starting in the 1970s when the U.S. Army wanted an alternative to the synchromesh manuals on its medium- and heavy duty trucks. Eaton briefly marketed a hydraulically operated AMT in the late '80s but withdrew it when it proved troublesome.

Almost a decade later came the AutoShift, with electronic controls that “talked” to engine controls; it changed gears automatically but required the driver to use a manual clutch while stopping or starting out from a stand-still. A few more years of development yielded the UltraShift, with an automated clutch and transmission both; it's called a “two-pedal” product because the driver operates the accelerator and brake pedals but no clutch pedal. It, too, had serious glitches, which engineers gradually eliminated but which caused initially enthusiastic fleet people to back away.

The UltraShift is in its third generation and works pretty well, according to fleet managers. However, the 10-, 13- and 18-speed AMTs are strictly on-road products, and Eaton has not officially approved it for on/off-road use, even if some can be found in such work. Instead Eaton engineers worked on a new series of AMTs, and now they're here, ready for consideration by people who run dumpers, mixers and other kinds of vocational vehicles. In short, AMTs ably take over much of the work of operating a truck and let drivers concentrate on traffic and delivering their loads.

Eaton calls this new product the UltraShift Plus, which is a good name because it adds useful features and capabilities to the earlier product's attributes, making the -Plus work as well in the dirt as on the pavement. When I heard that Eaton would have vocationally oriented AMTs I thought they'd include torque converters, but no – they have dry clutches.

UltraShift Plus comprises six models, three still for the highway and three for on/off-road use. The latter are designated Vocational Construction Series (VCS), Vocational Multipurpose Series (VMS), and Vocational Extreme Performance (VXP). They differ in number of ratios and intended chassis weights, but all are heavy-duty models which work very well. I drove several models in test vehicles at Eaton's proving grounds near Marshall, Mich., which includes a long paved oval track and tarmac area, steep test grades, and rough off-road trails.

Several weeks before an official product announcement late last summer, Eaton invited a handful of truck writers to Marshall for a preview. I returned about a month later for another hands-on experience. At the time, representatives said limited production would occur in late 2009 and full production would commence right about now, when you read this. Most truck builders should be offering the various UltraShift Plus versions, and dealer sales people should have information.

What I found was that UltraShift Plus will operate much more smoothly and smartly than most drivers can do with a manual transmission, and as good as the very best drivers. I concentrated on a pair of Kenworth T800 dump trucks that were identical in their specifications, which included Cat C15-475 engines, except for their transmissions: One had an 18-speed VXP and the other an Allison 6-speed 4500RDS. Both were loaded to about 65,000 pounds gross, according to Michael Holahan, program manager for the UltraShift Plus, who was my guide.

In my runs, the Allison of course worked smoothly and competently, and so did the Eaton VMS. Its clutch always engaged nicely, and the gearbox always shifted up and down quickly and smoothly. I could set the selector in Manual and tell the tranny what to do, but learned pretty soon that it was better to put it in Drive and leave it alone.

Usually the VMS skipped gears, and it worked so well with the engine that the staggered progressions were undetectable unless I listened to the revs or watched the LED gear indicator on the dash. For instance, it'd start out in 3rd, shift to 5th, then 8th, then 10th, and then further upward as we approached highway speeds. Or it'd start in 2nd, go to 5th, 7th and so on. It depended on whether we were on the level or an upgrade, and how hard I pressed on the accelerator.

On steep upgrades it seldom needed 1st gear to start out and could still skip a gear while accelerating. As some point the controls sensed that engine's output couldn't move us any faster, so would hang in an appropriate gear until we crested the top. It never missed a shift or chose the wrong gear for a situation. And it never ground a gear – something I couldn't say if I'd been operating a manual gearbox.

Engine revs seldom climbed toward redline and instead tended to stay below 1,800 or so, where fuel economy would be better. A light foot, of course, allowed upshifts even sooner in the rev range and made skip-shifting more appropriate. Downshifts accompanied any slowing of road speed, but again were smooth and almost imperceptible, except that when I got back on the accelerator pedal, yes, the-Plus's brains has chosen the correct gear and off we could go.

The -Plus is what earlier Ultra- and AutoShifts should've been, even if they were genuine work relievers compared to pure “crashboxes.” Gone are the clunky shifts and occasional confusion in the brains of the earlier products. The UltraShift Plus family is fully functional, and might well be as good as, or better than, the previous AMT smoothie, Volvo's I-Shift (Hands-On Trucking, CE April '09).

Eaton's -Plus helped the truck slow as well as go. Holahan was proud of how it worked with the Cat's Jake Brake, enabling strong retarding power down to about 3 mph with the selector in Drive. He pointed out that the Allison automatic in the other KW dumper released the Jake at 10 mph, and then the truck virtually free-wheeled downhill. Pulling the Allison into Manual and shifting it into 1st keeps the Jake working down to crawling speed, too, I told him on my second visit. But he noted that the UltraShift Plus also operates the Jake to less than 1 mph in Reverse, while the Allison doesn't work the Jake at all.

The -Plus has a hill-holder function that's clever and convenient on upgrades. Once the driver stops the truck with the service brakes and releases the brake pedal, the transmission controls work through the anti-lock braking system to keep the brakes applied enough to prevent the truck from moving backwards; it'll hold the brakes for exactly three seconds, and in that time the driver should step on the accelerator, which releases the brakes as the truck begins moving forward. What if he doesn't? In this test I waited while Holahan counted “one, two, three,” and on cue the holder released and the truck began drifting backwards; then I got on the gas, the clutch engaged smoothly and up we went. That's otherwise tricky to do without a lot of driving experience.

Such excellent behavior is the result of enhanced software, a newly designed electronically controlled clutch, load sensors, and refined actuators on the gearbox – something I can say in one sentence but that took three years of work by Eaton engineers and technicians and millions of miles of testing. Holahan said people at test fleets really like the products and their drivers love them. What I liked, aside from their smooth operation, was the UltraShift Plus's feeling of mechanical efficiency – engine power and torque coursing through solid steel gears instead of a torque-converter automatic's hydraulic mush. This should also mean better fuel economy, Eaton says.

Because Eaton compared its UltraShift Plus to Allison's automatic, so am I. The new -Plus is almost as easy to drive as the Allison, and I say “almost” because the Eaton has a clutch which can still be abused unless the driver is aware of it and cares enough to protect it. Having some experience driving a manual transmission would help. Both products have built-in safeguards to prevent intentional abuse. An Allison, though, can be given to a complete beginner with no worries, except that he or she must understand the possible dangers of driving a big and heavy truck.

So, there you go. Eaton people think their new UltraShift Plus series will accelerate the trend toward automated transmissions, and they're probably right. It should be priced less than a similarly rated Allison, and is so capable that you might well become part of that trend.