Test driving Eaton's Ultrashift demonstrator truck brought home the greatest advantage of an automated manual transmission: safety.

There are other benefits. Because every shift is a perfect shift with no clutch wear, maintenance costs are lower. The computer selects optimal shift points (when you want it to) so fuel economy is better. But as compelling as those benefits are, safety is the overriding one for me.

In the past, I've stab-braked and downshifted twice going down a 6 percent grade with Eaton's Autoshift. That's something I wouldn't even try once with a standard transmission. As our experienced readers know, even if you're in the wrong gear on a hill, you stay with it rather than risk missing a shift and getting caught completely out of gear.

While the Michigan terrain didn't give me the opportunity to repeat that, I did get to see the Ultrashift do its thing. Driving backcountry roads around Galesburg Mich. Ð headquarters for Eaton's Truck Components Operations and Roadranger Ð Bryan Beers, my guide from marketing, took me to some 3- and 4-percent grades I never knew existed so close to I-94. I had fun trying the Ultrashift in all its modes. I could control it when and how I wanted in "Manual" mode, or leave it to make perfect shifts on its own. It left me free to focus my attention on traffic and safety, not the mechanics of shifting.

The Ultrashift is an improvement on the Autoshift. Its most obvious feature is the elimination of the clutch pedal. It has a clutch, a hefty one with two 15-1/2 inch ceramic-faced plates, but a computer, not a pedal, activates it. There are now two shift control mechanisms available, plus some OEM designed options. You can choose between the flat panel push-button control, like the one in my test ride, or a shift knob more reminiscent of a floor shifter in a car. My preference would be for the shift knob. It's more intuitive. When in "Manual" mode (that replaces "Hold" in the Autoshift) working the lever should be quicker and easier than pushing the up or down buttons. Manual mode locks the transmission in gear to allow only driver-selected shifts. In "Low" mode, the Ultrashift only downshifts, and does it sooner for maximum engine braking. Low should be used mainly for downgrades and to get maximum rpm from the engine. A dash display shows the gear you're in.

If you attempt a shift that would take the engine rpm too high or too low, the control "beeps" to tell you it won't make the shift. If you brake or accelerate to bring conditions into line, it will then complete the shift.

My conclusion is that if we assume the new generation Ultrashift has all the Autoshift's bugs worked out of it, it will pay for itself in reduced clutch wear, lower maintenance costs due to less drivetrain shock and, of course, increased safety. Even the most skilled million-mile driver can have an off day, but as long as the computer keeps on computing and the X-Y Actuator floats the gears the way the computer tells it to, every shift will be perfect. There's enough to worry about on our streets and highways without having to care about a purely mechanical process. I say we concentrate on what's important and let machines serve our routine needs.

Bare Basics

• Truck: 2003 Kenworth T-2000 loaded to 69,580 pounds GCW.
• Engine: Caterpillar C-15 Bridge Engine: hp = 475 torque = 1650 pounds-feet
• Transmission: Eaton RTO-16910B-DM2 Ultrashift: 0.74 overdrive, 14,81:1 overall ratio
• Drive Axle Ratio: 3.55:1
• Tires: Bridgestone 285/75R 24.5