“When you have a great new engine with industry-leading torque and power, you must have a transmission that can handle it.”
Made for each other
TorqShift is mated with Ford’s all-new 6.0-liter Power Stroke® Diesel engine. The new five-speed automatic transmission features improved gear ratios, higher capacity pumps, robust components and simplified shift controls. These features contribute to fuel economy improvements, reliability, smooth shifts and quieter operation.
TorqShift features a selectable “tow-haul” mode that can be activated easily with a touch of a button or a touch of the brake, helping provide improved control when towing.
The new transmission also features a new control system that monitors the engine, transmission, overall vehicle speed and driver inputs to help optimize shift performance. TorqShift’s control body employs electronic solenoids to manage the transmission’s clutch elements, eliminating the variability experienced with more conventional hydraulic spring/valve systems. The solenoids are placed close to the clutches, minimizing response time.
At the heart of the new transmission is a larger pump to promote better lubrication and cooling. An external filter similar in concept to the filter on the engine features a replaceable transmission oil filter cartridge to aid removal of contaminants from the transmission oil.
The TorqShift cooling system more than doubled fluid pump size to move five gallons of cooling fluid per minute. Cooler lines have larger, half-inch passages to allow more fluid to pass through, and the system features new oil-to-air and in-tank coolers. The result is a transmission that runs approximately 50-70 degrees cooler than the previous transmission.
“This system has a very effective transmission cooler that allows us to deliver to the wheels as much engine power and torque as we want,” said Charlie Freese, chief engineer, diesel engines, Ford Motor Company. “It was very helpful to have a new engine and transmission coming in at the same time, because we developed them together and had the flexibility to optimize both. The engine is better because of the transmission, and the transmission is better because of the engine.”
Use of direct electronic shift control (DESC) improves clutch response and vehicle performance. DESC enabled engineers to eliminate a series of regulator and shift valves that previously delayed input response. The team replaced the regulator and shift valves with solenoids that directly control the clutch. In addition, an electronic system that updates approximately 125 times per second was included, dramatically improving responsiveness. Acceleration shift delays were reduced by more than half, using DESC.
Employing a five-speed transmission versus a four-speed improves launch and low-speed performance. In addition, it helps to improve fuel economy during highway driving in higher gears.
This was achieved by altering the gear ratios. The TorqShift first-gear ratio is 3.1 times the input in overall launch, for better punch when starting out. The smaller ratio transition of a five-speed results in less engine speed drop between shifts, better shift feel and improved response and progression during acceleration.
“This system is very reliable and has improved overall performance,” said Gerard Kuchta, TorqShift manager. “There are no surprises for the customer. There are no delayed shifts. There are no bad shifts.”
Up one side and down the other
A key feature of the TorqShift® transmission is the driver-activated tow-haul mode.
“When carrying a load in his truck, the driver simply pushes a button, and the shift strategy of the automatic transmission changes. The driver is letting the transmission know the truck is loaded,” explained Harry Rawlins, Super Duty trailer tow leader.
The new tow-haul mode allowed a more aggressive engineering calibration to make the transmission shift with more control on a loaded vehicle.
While going uphill, tow-haul mode holds a gear longer before upshifting to help maintain consistent travel without strain. During downhill runs, a tap on the brake signals tow-haul, triggering downshifts as appropriate to slow the vehicle. The driver experiences greater control and reduced need for downhill braking.
“Our customers haul very large loads,” said David Johnson, F-Series Super Duty vehicle engineering manager. “Tow-haul mode gives confidence and makes it feel like you’re not really working the truck, even when you are.”
Tests and more tests
“This engine and transmission have been a single system since program conception,” said Kuchta, “and they have undergone millions of miles’ worth of test time.”
The F-Series Super Duty powertrain was put through testing that measured how quickly, how well and how long it performs.
“In order to produce a product of the capability and quality that we wanted, we had to use all the tools that were available,” said Johnson. For example, testing was done against competitive vehicles for both sheer speed and capability.
In other testing of the new powertrain:
“We evaluated a significant sample of our current Super Duty customers, reviewing their driving habits and their type of routes, then we modified our test procedures to better represent them,” said Kuchta. “Not only did we increase the trailer loads and testing times, we modified the drive cycle to support tough conditions.”
Powering Auxiliary Equipment
To power auxiliary equipment like snowplows, aerial lifts, tow trucks or dump trucks, the new TorqShift also features a Power Take-Off (PTO) input gear and mounting pad on the side of the transmission case.
Production
TorqShift is produced at Ford’s Sharonville Transmission Plant near Cincinnati, Ohio. A series of in-process checks will be used to ensure consistent quality in the transmissions, said Kuchta. For every operation adding a component to the transmission, a separate station will make sure the ring is in place, the seal is tight or the part is seated.
“The system is designed to place each potential misbuild into a matrix, allowing the system to capture any error,” he said.
F-Series Super Duty trucks with the new powertrain are expected to be on sale in early 2003.