Acura 1994 Integra Service Manual page 394

The Automatic Transmission is a combination of a 3-e,ement torque convefter and triple-shaft electfonically controlled
automatic transmission which provides 4 speeds forward and 1 speed reverse. The entire unit is positioned in line with
the engine.
Torque Converter, Gears and Clutches
The torque converter consists of a pump, turbine and stator assembly in a single unit, The torque converter is connected
to the engine crankshaft so they turn together as a unit as the engine turns. Around the outside of the torque converter
is a ring gear which meshes with the starter pinion when the engine is being staned. The entire torque converter assem-
bly serves as a flywheel while transmitting power to the transmission mainshaft.
The transmission has three parallel shafts, the mainshaft. countershaft and sub-shaft. The mainshatt is in line with the
engine crankshaft.
The mainshaft includes the clutches for 1 st, and 2ndl4th, and gears for 3rd. 2nd, 4th, reverse and l st (3rd gear is in-
tegral with the mainshaft, while reverse gear is integral with the 4th gear).
The countershaft includes the 3rd clutch and gears Ior 3rd, 2nd,4th, reverse, lst and parking. Reverse and 4th gears
can be locked to the countershaft at its center, providing 4th gear or reverse, depending on which way the selector is moved.
The sub-shaft includes the lst-hold clutch and gears for 1st and 4th
The gears on the mainshait are in constant mesh with those on the countershaft and sub-shaft. When certain combina-
tions of gears in the transmission are engaged by the clutches, power is transmitted from the mainshaft to the counter-
shaft via the sub-shatt to provide @, E, tr. tr and @ position.
Electronic Control
The electronic control system consists of the Transmission Control Module {TCM), sensors, and 4 solenoid valves. Shift-
ing and lock-up are electronically controlled for comfortable driving under all conditions.
The TCM is located below the dashboard, behind the left side kick panel on the driver's side.
Hydraulic Control
The valve bodies include the main valve body, secondary valve body, regulator valve body. servo body, and lock-up valve
body throuqh the respective separator plates.
They are bolted on the torque converter housing.
The main valve body contains the manual valve, 1-2 shift valve, 2-3 shift valve, Clutch Pressure Cont.ol (CPC) valve,
4th exhaust valve, relief valve, and oil pump gears.
The secondary valve body contains the 4-3 kick-down valve,3-2 kick-down valve,2-3 orifice cont.ol valve, 3-4 shitt
valve, orifice control valve. modulator valve, and servo control valve
The regulator valve body contains the pressure regulator valve. lock-up control valve, torque converter check valve, and
cooler check valve.
The servo bodv contains the servo valve which is integrated with the reverse shift fork, throttle valve B, and accumulators.
The lock-ug valve bodv contains the lock-up shift valve and lock-up timing B valve. and is bolted on the secondary valve
body.
Fluid from the regulator passes through the manual valve to the various control valves.
Shitt Control Mochanism
Input to the TCM i.om various sensors located throughout the car determines which shift control solenoid valve should
be activated.
Activating a shift control solenoid valve changes modulator pressure, causing a shift valve to move. This pressurizes
a line to one of the clutches. engaging that clutch and its corresponding gear.
Lock-up Mechanism
In @
position. in 2nd, 3rd and 4th, and E
position in 3rd, pressurized tluid can be drained from the back of the tor-
que converter through an oil passage, causing the lock-up piston to be held against the torque converter cover. As this
takes Dlace, the mainshaft rotates at the same speed as the engine crankshatt. Together with hydraulic control, the TCM
optimizes the timing ol the lock-up mechanism.
The lock-up valves control the range of lock-up according to lock-up control solenoid valves A and B, and throttle valve B
When lock-up control solenoid valves A and B activate, modulator pressure changes. Lock-up control solenoid valves
A and B are mounted on the torque converter housing, and are controlled by the TCM.
(cont'd)
14-3