The Ford ATX is a 3-speed
automatic transaxle that uses a Ravigneaus planetary gear train. The
gear-type oil pump is driven indirectly by the torque converter. Because
the oil pump is located at the opposite end of the transaxle, as is the
torque converter, a drive shaft is used to rotate the oil pump.
The transaxle has been
continuously updated and modified to fit different applications. The
most obvious changes made to the transaxle are the torque converter. The
ATX has been available with three different designs of torque
converters: the conventional three-element converter, a converter with
centrifugal lock-up, and a split-torque converter.
The original ATX
transaxles were equipped with a splitter gear torque converter. This
unit contained a planetary gearset that divided the delivery of input
torque. Part of the torque is transmitted mechanically and the remainder
by fluid force on the torque converter's turbine. In second gear, 62
percent of the torque is transmitted mechanically, while in third gear
93 percent is mechanically transmitted. In low gear and reverse, full
engine torque is transmitted by normal converter fluid flow.
The split-torque converter
is used in Escort and Lynx ATX transaxles and in the transaxles of
1984-86 Tempo and Topaz models. The ATX used in the Taurus and Sable
models used a centrifugally locking torque converter. By 1988, all ATX
transaxles used in the Tempo, Topaz, Taurus, and Sable models were
equipped with a conventional fluid-linked torque converter.
The small sun gear of the
ATX gear train is called the reverse sun gear and is meshed with the
short pinion gears. The short pinion gears serve as idler gears between
the reverse sun gear and the long pinion gears. The large sun gear is
called the forward sun gear and it meshes with the long planetary pinion
gears. The short pinion gears are meshed with the long gears and both
sets of pinions can rotate on their own shafts held by the carrier. The
planetary carrier serves as the output for the gear train. The ring gear
surrounds the other members of the planetary gearset. The long pinions
are in constant mesh with the short pinions, the forward sun gear, and
the ring gear.
The ATX is equipped with
three multiple-disc clutches, one band, and a one-way roller clutch. The
parking gear is located on the output gear of the final drive assembly.
Refer to the clutch and
band application chart given at below.
|
Gear
Selector Position |
Operating Gear |
Front
Band |
Top-Gear Clutch |
2nd
Gear Clutch |
Reverse Clutch |
One-Way Clutch |
| P-Park |
None |
|
|
|
|
x |
| R-Reverse |
Reverse |
|
x |
|
x |
x |
| N-Neutral |
None |
|
|
|
|
x |
|
D-Drive |
1st gear |
x |
|
|
|
x |
|
|
2nd gear |
x |
|
x |
|
|
|
|
3rd gear |
|
x |
x |
|
|
|
2-Second |
1st gear |
x |
|
|
|
x |
|
|
2nd gear
|
x |
|
x |
|
|
|
1-Man.
2nd |
1st gear |
x |
x |
|
|
x |
Power Flow In Neutral
When the gear selector is placed into neutral or park, the one-way
clutch locks the input from the torque converter's turbine shaft to the
sun gear. Since no other clutch or band is applied, power does not flow
through the gear train. When the gear selector is in park, the parking
gear is locked to the transaxle case by the parking pawl.
Power Flow in First
Gear The one-way roller clutch locks and allows the reverse sun gear
to be driven by the turbine shaft. The reverse sun gear drives the short
pinion gears in a counterclockwise direction. The short pinions, in
turn, drive the long pinion gears in a clockwise direction. The long
pinions walk around the forward sun gear, which is held stationary by
the front brake band and drive the planet carrier and final drive
clockwise. The top gear clutch is applied in manual low to provide for
engine braking.
Power Flow in Second
Gear Engine torque is transmitted through the planet carrier to the
applied second gear clutch, which locks the intermediate shaft to the
ring gear. The front brake band is also applied and holds the forward
sun gear. The turning of the ring gear causes the long pinion gears to
rotate clockwise and walk around the forward sun gear. This action
drives the planetary carrier and final drive clockwise.
Power Flow in Third
Gear When operating in third gear, the second gear clutch of the ATX
remains applied and locks the intermediate shaft to the ring gear. The
top gear clutch is also applied and locks the reverse sun gear to the
turbine shaft. Since the planetary gear train has two inputs, direct
drive results. By allowing input on both the reverse sun gear and the
ring gear, the long and short pinion gears are trapped between the ring
gear and reverse sun gear. The planetary carrier is the output.
Power Flow in Reverse
while operating in reverse gear, the ATX applies the reverse clutch,
which holds the ring gear. The applied top gear clutch and one-way
clutch lock the reverse sun gear to the turbine shaft. The clockwise
rotation of the sun gear causes the short pinion gears to rotate in a
counterclockwise direction. The short pinion gears drive the long pinion
gears in a clockwise direction; however, since the ring gear is held,
the planetary carrier is forced to rotate in a counterclockwise
direction. The carrier drives the final drive and the vehicle moves in
reverse.