The first product from the newly formed ZF Meritor transmission joint venture is a fully automated, two-pedal heavy-duty transmission for class-8 trucks. Called the Freedom Line, it gets its name because it frees the driver from use of the clutch pedal. The result is a truck that drives much like the family car in most driveways in North America.

The technology comes from ZF of Germany, with an automated mechanical single-plate clutch actuated by an air cylinder and controlled electronically. Behind this is a twin-countershaft transmission of either 12 or 16 speeds, according to the torque rating of the transmission. This has an electronic control unit connected to the engine via an SAE J-1939 link. Gear shifting is electro-pneumatic, with all the control and logic functions contained in a box mounted on the top of the aluminum transmission case. The models on display at the November launch at the American Trucking Associations annual convention featured a joystick shifter mounted to the driving seat.

TRANSMISSION DETAILS

The basic gearbox is a twin countershaft splitter/range-change box. The constant mesh, non-synchronized transmission family was designed from the start for world applications with suitability for North American and European duty cycles. The transmission already is introduced in Europe as the AS Tronic.

Gears are helical cut for quiet operation, and there are 12 ratios for the 1450 pound feet transmission and 16 ratios for the 1650/1850-rated unit. The splitter/ range-change transmission is integral with the clutch housing, which has an air cylinder at the bottom to actuate the clutch release fork. Unique to North America are the input and output shafts, and the 12-volt power of the control unit.

TWO PEDALS

On the road, the Freedom can be shifted automatically or at the driver’s will. On the demo, the joystick could be used to select/deselect fully automatic operation. In driver-select mode, you bump the joystick forward to upshift and back to downshift.

Under a light load, the transmission can be instructed to skip shift by bumping the stick twice. To move forward, turn the rotary switch from “N” to “D”; a display indicates which gear is selected for take-off, and the driver can override. In the case of our loaded Freightliner Century Class tractor and trailer with Detroit Diesel power, this was third gear.

Unlike car and powershift automatics, there is no creep with the ZF Meritor automatic. Once you select Drive and the gear is engaged, you hold out the clutch until pressure is exerted on the throttle (feed the power in very gently to avoid too great a torque reaction in the low ratios).

Underway, the transmission shifted progressively, responding to the amount of throttle demand with higher rpm shift points. It faultlessly chose ratios for every driving situation; hill starts were easily accomplished using a little trailer hand valve to hold the truck on the grade. Of course, with no clutch, two-foot, two-pedal driving can be used, allowing for the foot treadle to be used in a hill start.

Using the transmission on manual selection allowed for the best minimum-rpm take off and for manoeuvring in a parking lot. However, most drivers will almost certainly opt for automation most of the time.

The deep reduction of the lower reverse ratio allowed for excellent control backing under a trailer or up to a dock. Uniquely, the transmission can be shifted to reverse high when in motion, should the truck need to be moved a distance in reverse.

THE BOTTOM LINE

No pricing has been set for the Freedom Line transmissions, though there will be a 15 to 20% premium over the Meritor SureShift. Some cost savings will be realized by the truck manufacturer in eliminating the clutch pedal and actuation mechanism. Customer payback is expected from less driveline damage, as much as a 5% improvement in fuel economy, and lower accident rates. From the driver’s perspective, the elimination of both clutch and gearshift controls means less fatigue and more space in the cab for greater driving comfort.

SIDEBAR:

ROAD NOTES: ZFMeritor’s Freedom

O With its aluminum clutch housing, the Freedom weighs 550 pounds, more than 100 pounds lighter than competitive automated transmissions.

O Production models, available next fall, will have the Meritor seat-mounted shifter used on the SureShift transmission. It’s anticipated that any transmissions offered by Freightliner will be available with its steering-column-mounted shifter.

O About the only caution necessary is to take care with the brakes released and the truck ready to go-it can start to roll, just like a standard transmission, if you don’t hold the truck on the foot or hand valve.