Acura 2002 RSX Service Manual page 552

Automatic Transmission
System Description
General Operation
The automatic transmission is a combination of a 3-element torque converter
and triple-shaft electronica y controlled
unit which provides 5 speeds forward and 1 reverse. The entire unit is positioned
in tine witrr tne engine.
Torque Converter, Gears, and Clutches
The torque converter consists of a pump, turbine, and stator assembly in a
single unit. The converter housrng (pump)
rs connected to the engine crankshaft and turn as the engine turns. Around
the outside ofthe torque converter is a ring
gear which meshes with the staner pinion when the engine is
being started, The entire torque converter assembry
serves as a flywheel while transmitting power to the transmission mainshaft.
the transmission has three parallel
shafts; the mainshaft. the countershaft and the secondary shaft. The mainshaft
is in line with the engine crankshaft,
and includes the 4th and sth clutches. and gears for sth, 4th, reverse, and idler.
The mainshaft rever'se gear rs rntegral
with the mainshaft 4th gear. The countershaft includes the gears for 1st, 2nd, 3rd,
4th. bth, reverse, park, and the final
drive. The final drive gear is integral with the countershaft. ihe countershaft
4th gear and th" "oun[i.h"ft
r"u"r."
gear can be locked to the countershaft providing the 4th or reverse gear,
depending on which way the setector is
moved The secondary shaft includes the lst, 2nd, and 3rd clutchesland gears for
ist, znd, gro, and idler. The idler
shaft is located between the mainshaft and secondary shaft. and the idleigear
transmits powei between the mainshaft
and the secondary shaft. The gears on the mainshaft and the secondary shaft
are in constant mesh with those on the
countershaft. When certain combinations of gears in the transmission are engaged
by the clutches, power is
transmitted through the mainshaft, then to the secondary shaft to the countershaft provide
drive.
Electronic Control
The electronic control system consists of the powertrain control module (pcM),
sensors, and solenoid valves, shifting
and lock-up are electronically controlled for comfortable driving under all conditions.
The pcM is located betow the
dashboard, under the glove box.
Hydraulic Controt
The valve bodies include the main valve body, the regulator valve body,
and the servo body. They are botted to the
torque converter housing. The main valve body contains the manual valve,
the shift valvesi, a. C, anJg, tne ,etiet
valve. the lock-up contror varve, the coorer check varve, the servo contror varve.
and the ATF pump gears. The
regulator valve body contains the regulator valve, the torque converter check
valve, lock-up shift va]ve, and the 1st
and 3rd accumulators. The servo body contains the servo valve, the shift valve
D, accumulators for 2ni, +th, and sth,
and shift solenoid valves for A, B, c. o, and E. Fluid from the regulator passes
through the manual valve to the various
control valves. The 1st, 3rd, sth clutches receive fluid from thei; respective feed pipes,
and the 2nd andine qtn
clutches receive fluid from the internal hydraulic circuit.
Shift Control Mechanism
The PCM controls to shift gears the shift solenoid valves A, B, C. D, and E, and
the A,/T clutch pressure controt solenoid
valvesA, B. and C, while receiving input signals from various sensors
and switches located tirroughouiil,e ueni"te.
The shift solenoid valves shift the positions of the shift valves to switch the port
leading hydraulic-pressure to the
clutch The A'/T clutch pressure control solenoid valves A, B. and c regulate
their respective pressure, and pressurize
to the clutches to engage it and its corresponding gear. The pressures of the A,/T
clutch pressure control sotenoid
valves also apply to the shift valves to switch the Dort.
Lock.up Mechanism
The lock-up mechanism operates in E position (2nd,3rd,4th and 5th), in
E position (2nd and 3rd), and M {sequential
sponshift mode) position (3rd, 4th and sth). The pressurized fluid is drained
irom the back of trr" torqr"-"onu"n",
through a fluid passage, causing the torque converter clutch piston to be
held against the torqua "on-uJ", "ou"r. n,
this takes place, the mainshaft rotates at the_same speed as the engine crankshaft.
Together with the hydraulic control,
the PcM optimizes the timinq and volume of the lock-up mechanis;. when
the shift solenoid valve E is turneo on oy
the PcM, shift solenoid valve E pressure switches the lock-up shift valve lock-up
on and off. The A,/T clutch pressure
control sorenoid varve A and the rock-up contror varve contror the vorume of
the rock-up conditions.
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