The gorgeous Kenworth W900L I’d been driving all day was great, and there was no snarling traffic to deal with on the lesser highways of north-central Michigan. But at the end of the day I was uncomfortable.

It was the transmission. The darned thing was just so good that I thought I hadn’t worked hard enough to make it burp or blush or otherwise lose its perfect composure.

I’m talking about the new ZFMeritor FreedomLine, North America’s first heavy-duty transmission to lose its clutch pedal without losing its clutch-and without adding a torque converter. It actually does have an ordinary clutch but it’s operated automatically by way of pneumatic and of course electronic controls. And there really is no clutch pedal. Unlike competing automated mechanical gearboxes, and ZFMeritor’s own SureShift, both starting and stopping are accomplished with the throttle and brake pedals alone.

Developed by ZF Friedrichshafen, Europe’s largest transmission maker, and the ZFMeritor joint venture of ZF and ArvinMeritor, the FreedomLine is that partnership’s first product. In Europe it’s dubbed the ASTronic, but its first generation has been available exclusively in Iveco trucks for a couple of years as the EuroTronic-also clutchless, but the driver initiates the shifts.

With the addition of full automation and quiet-running helical-cut gears, the FreedomLine will be available here late this year, likely in Freightliner, Kenworth, and Peterbilt trucks first.

THE TECHNOLOGY

The FreedomLine is a familiar twin-countershaft design with splitter/range-change box, integrated with the clutch housing which has an air cylinder at the bottom to actuate the release fork. Unlike other European transmissions, this is a constant-mesh, non-synchronized gearbox, though there are synchronizers on the range-change and splitter.

Significantly, it was designed from the start for automation, not based on an existing manual with electronic controls overlaid. It was also created for both North American and European duty cycles.

Features unique to North America include the input and output shafts and the 12-volt power of the electronic control unit, connected to the engine via an SAE J-1939 link. The electronic interface is also for this market alone, which allows for J-1587 diagnostics and flexibility in the driver interface. It uses the existing ZFMeritor SureShift joystick mounted to the seat, though other mountings are possible.

The FreedomLine is available in 12- and 16-speed versions, direct or overdrive in each case, with torque capacities from 1450 to 1850 pound feet. The 12-speed’s overdrive ratio is 0.78:1, while the 16-speed’s is a rather mild 0.83. Steps between gears in the 16-speed are between 18% and 21%. In the 12-speed they’re mostly 29%. The 12-speed weighs in at 550 pounds, 594 for the 16, quite a bit less than its rivals.

The dry clutch is a mechanical single-plate type with an organic facing, which explains the very “soft” startoffs I experienced. It’s a 430mm or 17-inch clutch, and you have no choice here, which may bother folks and probably shouldn’t. Other automated mechanical transmissions also demand specific clutches.

The bigger issue here may be the single-plate matter. Is it going to hold up?

ZFMeritor director of sales and marketing Charlie Allen points out that along with lots of testing, loads of real miles have been run in Iveco trucks with the EuroTronic, and experience there shows that clutch life has actually been extended by two or three times compared with manual gearboxes.

“We don’t think it’s an issue,” says Allen, who rode shotgun on my test drive.

That’s important, because the FreedomLine doesn’t float-shift the way an experienced driver can do. It uses the clutch on each shift. It commands the engine to reach synchronous, but doesn’t use the engine brake to help out. It retards the spinning of the transmission itself, using an inertia brake on the driver-side countershaft. It’s different from the approach we’re used to.

BUT DOES IT WORK

You bet. This transmission takes automation technology to a new level with consummate skill. It actually seems to know what you’re thinking.

The FreedomLine reacted so quickly and accurately to changing road and throttle conditions that it seemed to have a mind of its own. Its response never seemed to be the same, as it skipped gears in one set of circumstances but not in another, even though they were more or less similar.

Obviously, it had detected even minor differences in engine loading. Engineering types call this “adaptive” technology-it adapts to new situations on the fly.

That adaptive skill was obvious right from the start of my test in Troy, Mich., where ArvinMeritor is headquartered. Yes, Michigan, with no great hulking hills but lots of traffic and shifting as I tried to stay off the interstates as much as possible. Charlie and I drove north looking for a grade or two.

Getting the big Kenworth rolling in the first place was no sweat with the 16-speed overdrive version. The truck had a prototype gear selector, similar to SureShift, mounted to the side of the seat-with a rotary switch offering a choice of R, N, or D and a joystick to shift up or down, with a “function button” for going to fully manual operation. To shift manually, you bump the stick forward to upshift, back to downshift.

You can also make it skip-shift. The clutch is held until you feed it some fuel, and then you get a smooth takeoff, whether your foot’s to the floor or not. No muss, no fuss, no jerky motions. Unlike a car, there’s no “creep.” You just select “D,” apply some throttle, and go.

All shifts were made smoothly, even at full throttle (you don’t have to lift your right foot). You do have to remember that there’s a clutch when you’re on a grade. The truck will roll back just like a standard transmission if you don’t use the foot brake or the spike.

The transmission runs a diagnostic test automatically on startup. Fault codes show on a small dashboard display, which also tells you which gear you’re in. The test truck had the Cummins RoadRelay display, so we could keep track of engine load and other stuff as well.

We grossed just 73,000 pounds, and the transmission knew it had a 600-horse Cummins ISX engine with 1850 pound feet of grunt, so it launched the KW in fourth gear pretty regularly. You can over-ride that choice if you want.

On the flat, left in automatic and with light throttle, the FreedomLine frequently shifted right to sixth, on to seventh, and then skipped up to 11th. Sometimes it went from fourth to fifth and then straight to eighth. Sometimes it would skip from 12th to 14th, sometimes not. It shifted more or less progressively, letting the engine run a little further into the tach if I “asked” for more revs. Most shifts were done at around 1500 rpm.

Downshifts were similarly unpredictable, and were not done gear by gear by gear, rather by appropriate skip-shifts. One of my driving habits, maybe a bad one, is not to downshift through several gears as I approach a corner or an exit ramp. Rather, I’ll drop a cog or two and then let the engine die in gear, hit the clutch as it starts to lug, and then find the next gear I need to accelerate out of the turn. I may have left 11th and then need sixth, for example, and that’s exactly what the FreedomLine did (somewhat more effectively than I do!).

As soon as I throttled up, it found the right gear instantly and off we went. The transmission obviously adapted to me just as much as to load and road, which should inspire confidence quickly. FINALLY, A HILL

Michigan doesn’t have a lot of hills, so the bridge over the Zilwaukee River on I-75 was the best we could find, a fairly long grade in the 6% range. With approach roads on either side, it was easy to make several runs trying different strategies-sometimes from a dead stop on the grade, maybe just vaguely rolling with the engine lugging, sometimes manually, other times on auto pilot. On a few runs I put my foot right to the floor and left it there, on others I was more gentle.

Regardless, the transmission didn’t care, and in every case-thanks largely to the big engine-it even managed to skip at least a couple of the lower gears. On one automatic run from a dead stop with the dash display reading fourth gear at the base of the hill-and the RoadRelay showing 100% engine load all the way-it shifted to fifth, skipped to eighth, and then went gear by gear all the way to 16th. All shifts were made at about 1700 rpm except for the last one, where the electronics let the engine run out to 1950 rpm-responding, I guess, to the fact that my right foot was still planted. It was probably also trying to ensure that it really could hold 16th to avoid “hunting” for a gear. In fact, it never once went hunting the whole day.

Also impressive is the gearing in reverse. The deep reduction of the lower reverse ratio (13.07:1 in the 16-speed overdrive) allows for excellent control in backing under a trailer or up to a dock. You can even shift into reverse high.

CONCLUSION

I wish I could find something about the FreedomLine to question, but I can’t. It’s that good. And I’m no longer feeling that I didn’t try hard enough to make it hiccup. One of the few other people to have given the FreedomLine a proper test came away with the same feeling. He’s an engineer and expert driver, not associated with ZFMeritor, and he played hard on a 16% grade. On that devilish hill, he tells me, the transmission once chose the wrong gear for a downshift-but corrected itself instantly and never did it again.

The FreedomLine’s behavior shows just how much work went into its original design and subsequent development. It’ll cost more than a manual, but drivers will gain a lot-like the ability to concentrate on the road with a lot less stress. There should be a small fuel-economy advantage as well, maybe as much as 5% in some cases. And, of course, for fleet owners looking at new sources of drivers, the FreedomLine should cut training costs and widen the talent pool.

It’ll be interesting to see where this technology takes us. In the meantime, it should win converts from amongst those who say they wouldn’t buy an automatic.

Sooner or later, though, automation will not be a minority choice.