four wheel drive ACURA RL KA9 1996 Service Repair Manual

Description

The automatic transmission is a combination of a 3-element torque converter and a dual-shaft electronically controlled

automatic transmission which provides 4 speeds forward and 1 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, assembled in a single unit. They are connected to the engine

crankshaft so they turn together as a unit as the engine turns. Around the outside of the drive plate is a ring gear which

meshes with the starter pinion when the engine is being started.

The entire torque converter assembly serves as a flywheel while transmitting power to the transmission mainshaft.

The transmission has two parallel shafts: the mainshaft and the countershaft. The mainshaft is in line with the engine

crankshaft. The mainshaft includes the 1st, 4th and 2nd clutches and gears for 4th, 1st, 2nd and reverse (3rd gear is integral

with the mainshaft). The countershaft includes the 3rd, 1st-hold and reverse clutches, and gears for 3rd, 4th, 1st, 2nd,

reverse and park. The secondary drive gear is integrated with the countershaft. The gears on the mainshaft are in constant

mesh with those on the countershaft. When certain combinations of gears in the transmission are engaged by clutches,

power is transmitted from the mainshaft to the countershaft to provide , , , and positions.

Electronic Control

The electronic control system consists of a Powertrain Control Module (PCM), sensors, a A/T clutch pressure control solenoid

and four solenoid valves. Shifting and lock-up are electronically controlled for comfortable driving under all conditions.

The PCM is located below the dashboard, under the front lower panel on the passenger's side.

Hydraulic Control

The lower valve body assembly includes the main valve body, the secondary valve body, the throttle valve body, the

solenoid, the shift solenoid valves and the ATF passage body. They are bolted on the lower part of the transmission hous-

ing. Other valve bodies, the regulator valve body, the ATF pump body and the accumulator body, are bolted to the torque

converter housing.

The main valve body contains the manual valve, the 1-2 shift valve, the 2-3 shift valve, the 3-4 shift valve, the 4-3 kick-down

valve and the main orifice control valve. The secondary valve body contains the 3-4 orifice control valve, the 4-3 shift timing

valve, the line pressure control valve, the modulator valve and the accumulator pistons. The throttle valve body includes

the throttle valve which is bolted onto the secondary valve body. The A/T clutch pressure control solenoid is joined to the

throttle valve body. The regulator valve body contains the regulator valve, the lock-up shift valve and the cooler relief valve.

Fluid from the regulator passes through the manual valve to the various control valves. The ATF pump body contains the

lock-up timing valve, the lock-up control valve and the relief valve. The torque converter check valve is located in the torque

converter housing under the ATF pump body. The accumulator body contains the accumulator pistons. The reverse accu-

mulator and the 1st-hold accumulator pistons are assembled in the rear cover.

The 1st, 1st-hold, 2nd and reverse clutches receive fluid from their respective feed pipes, and the 3rd and 4th clutches

receive fluid from the internal hydraulic circuit.

Shift Control Mechanism

Input from various sensors located throughout the vehicle determines which shift solenoid valve the PCM will activate.

Activating a shift solenoid valve changes modulator pressure, causing a shift valve to move. This pressurizes a line to one

of the clutches, engaging the clutch and its corresponding gear.

Lock-up Mechanism

In position, in 2nd, 3rd, and 4th, and position in 3rd, pressurized fluid is drained from the back of the torque con-

verter through a fluid passage, causing the lock-up piston to be held against the torque converter cover. As this takes

place, the mainshaft rotates at the same speed as the engine crankshaft. Together with hydraulic control, the PCM opti-

mizes the timing of the lock-up mechanism. The lock-up valves control the range of lock-up according to torque converter

clutch (lock-up control) solenoid valves A and B, and throttle valve. When torque converter clutch (lock-up control)

solenoid valves A and B activate, modulator pressure changes. The torque converter clutch (lock-up control) solenoid

valves A and B are mounted on the torque converter housing, and are controlled by the PCM.ProCarManuals.com

Troubleshooting

DTC 71: Abnormal Wheel Speed Signal

Are any DTCs except 71 indicated?

Check the tires.

Are tires with specified size and

inflated to specification?

Check for brake drag.

Do the brakes drag?

Visually check for appropriate

wheel sensor and pulser installa-

tion (see table).

Are they installed correctly?

Check the four pulser gears for a

chipped tooth (see table).

Is the pulser OK?

Problem Verification:

1. Clear the DTC.

2. Test-drive the vehicle at 19

mph (30 km/h) or more.

3. Verify the DTC.

Is DTC 71 indicated?

YES

Check for loose terminals in the

VSA control unit 42P connector.

If necessary, substitute a known-

good VSA modulator-control

unit, and recheck.
Preform the appropriate trou-

bleshooting for the DTC.

Replace the tire(s) with the spec-

ified size.

Repair the brake drag.

Reinstall or replace the wheel

sensor or pulser.

Replace the driveshaft or hub

unit. (Chipped pulser gear.)

The system is OK at this time.
Verify the DTC.ProCarManuals.com