Ford's 3.5-liter twin-turbocharged, direct-injected EcoBoost V-6 engine, set to debut this spring under the hood of the Lincoln MKS and, makes so much torque (350 pound-feet, to be exact) that apparently the automaker's standard 6F-50 six-speed automatic transmission couldn't reliably handle it. So Ford went back to the drawing board and created a new transmission specifically for the higher torque demands of the new powerplant: the 6f-55 automatic transmission.
While most of the details are highly technical in nature, the key changes for this new transmission include stronger parts and materials to deal with the increased forces and temperatures present in the turbocharged power train. For example, the 6f-55 transmission features thicker transfer and final gears and a new, more robust differential case.
Because the EcoBoost engine's primary goal is increased efficiency, the 6f-55 transmission also features a battery of changes that allow it to operate with less friction and at more efficient temperatures.
In the case of units destined for use on Lincoln models, extra dampening is supplied by a second roll restrictor, which supposedly reduces drivetrain noise, vibration, and harshness.
Other 2010 products set to offer this power-train combination include the Ford Flex and Lincoln MKT.