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Super Duty's super tranny
Transmissions get little
attention – until they shell out under heavy work. Realizing that a lot of that
work takes place at low engine rpm, Ford engineers created a new TorqShift design
(shown above with the 6.7-liter diesel) fashioned to better manage the low-end
torque produced by their new Power Stroke diesels. The 6R140 transmission
employs a Lepelletier-style power flow, which reduces the complexity in
connecting the gear sets and clutches. The six speeds require only five
clutches, and the speeds of the clutches relative to one another are low, which
To handle the torque of the
6.7-liter diesel, Ford strengthened the tranny by utilizing a powder-metal carrier
in the compound planetary gear set. The carrier consists of four pressed
powder-metal components brazed together for a rigid structure. “The
sinter-brazed gear set enables more torque capacity and greater engine speed
capability,” explains Ford engineer Al Bruck. “Also, a deep first-gear ratio
and two overdrive gears create a wider ratio span. This is combined with
available lower-axle gear ratios and a control system that automatically
selects the most efficient shift schedule.”
Then, too, the TorqShift is
feature-rich. For example, it includes the Progressive Range Select feature,
which allows you to reduce the range of available gears while in drive mode.
This feature will allow for limited use of upper gears when heavily loaded or
while towing on grades.
And for full manual
function, you can pull the shift lever into “M” for manual mode and use the
Range Select toggle to change gears. The control system locks the torque
converter, holding a particular gear for a full manual transmission operation.
Hey, It’s Got A PTO Drive!
Another addition (and a good
fit for agriculture) is the Live Drive PTO. This option (available only on
diesel engines) is linked through the torque converter to the engine
crankshaft. The PTO’s output gear is linked through the torque converter to the
engine crankshaft and is available anytime the engine is running.