Summer saw the American launch of Volvo's I-Shift automated 12-speed transmission in Savannah, Ga. In the fall we journeyed to Toronto, Canada, to revisit the Eaton UltraShift in its 13-speed heavy-duty and six-speed medium-duty applications. And now we have completed the automated circle with a trip to Troy, Mich., to again drive the ZF Meritor FreedomLine 12-speed.

Like Volvo's transmission, the FreedomLine traces its heritage to Europe, where, as the ZF AS Tronic, it has enjoyed relative popularity and an enviable reputation for robustness and sophistication. As the FreedomLine, the German automated transmission is dressed in Laurenberg, S.C., with features such as 12-volt electricals and software and shifting designed to suit American duty cycles.

ZF is relatively unknown in North America, though it is one of the world's major automotive suppliers. For instance, probably half of that BMW you may be lusting after is made by ZF. And ZF is a big supplier of heavy-duty steering and suspension components for trucks in Europe. But ZF is best known for gearing with light, medium and heavy transmissions. In fact the company name is Zahnradfabrik Friedrichshafen A.G., meaning "gear factory" company in Friedrichshafen, Germany. Originally it was an offshoot from the empire of Count Zeppelin, created to make the angle drives for the propeller shafts on the early airships that carried the engines inboard.

But while the mechanicals have a fine pedigree, what makes the FreedomLine such a useful transmission is the powerful electronic management of the clutch and shifting. For like the very advanced Volvo I-Shift, the FreedomLine uses a dry clutch and an electro-pneumatic operation that opens the clutch during gearshifts. It will also look at the engine and road speeds and skip-shift if it decides conditions are right.

Taking a brief drive from ArvinMeritor's Troy headquarters, Charlie Allen and I headed for one of Detroit's busy freeways. I reveled in the ease of driving the Kenworth W900L, even in heavy urban traffic. Starting out was easy, with the transmission picking up second gear and launching as I touched the accelerator. The truck picked up speed, the transmission picked up gears and I watched out for the traffic while chatting with my old friend Allen. He's a major booster for the FreedomLine and has been with it four years of the decade it has been in the market here, first in the joint venture of ZF Meritor and now with Meritor.

He explained that it would take the transmission a few blocks to learn the load on the truck and the way I like to drive, then adjust its shifting to suit. And sure enough, it knew I wanted it to shift early because I told it so by lifting my foot off the accelerator to initiate the upshifts.

The FreedomLine also responds to commands from the short, seat-mounted shifter if the auto/manual button is depressed – if the engine rpms are within limits for the next gear.

Slowing for an offramp to swing around back for Troy again, the transmission recognized the retarder was on and adjusted the shift points to get the maximum benefit, downshifting for maximum braking rpms. Then it was back on the onramp, where I stomped on it. The transmission snapped through the gears, getting swiftly up to speed to merge with traffic. Here, the retarder occasionally assisted in bringing down rpms during an upshift to quickly synchronize gear speeds and re-engage the clutch in the shortest possible time.

Back at the test labs that stretch back behind the corporate ArvinMeritor headquarters I swung around, hit the button on the shifter to select neutral, then selected reverse and backed up, nice as you please. The I-Shift does this too, but backing up is a feat that is more tricky with the centrifugal clutch of the UltraShift transmission.

Allen says fleets that have tried the FreedomLine generally get hooked – not only because drivers like them, but because they enable the fleet to pick up fuel economies, both from inexperienced drivers and veteran gearjammers. And drivelines have a much easier life with the smooth-shifting transmission, reducing maintenance costs.

I'm betting those fleets also see a reduction in fender benders and sideswipe claims because drivers have more time to watch out for traffic instead of rowing the truck along with the gearshift.