1991 ACURA NSX torque

Preset Torque

Inspection
On-Car:

1. Lift up right rear wheel,
and place the safety stand.

(Lift and Support Points, see section 1).
2. Block the other three wheels.
3. Measure preset torque clockwise using a torque wrench as shown.

Standard:
60–140 N·m

(6–14 kg-m, 43–101 Ib-ft)

Service Limits: 30 N·m (3 kg-m, 22 Ib-ft)

TORQUE WRENCH
RIGHT REAR WHEEL SAFETY STAND

4. If preset torque is less than the service limit, replace the clutch discs with new ones.
NOTE: Adjust the thrust shim whenever the clutch
discs are replaced (see page 15-22).
Assembly:

1. Place one special tool in a vise. Place the left side of the differential assembly on the special tool, then
preset the differential with 3 – 5 rotations, both
clockwise and counterclockwise.

DIFFERENTIAL
INSPECTION TOOLS

07MAJ– PR90100

2. Measure preset torque clockwise using a torque wrench as shown.

Standard: 60–140 N·m
(6–14 kg-m, 43–101 Ib-ft)

Service Limit: 30 N·m (3 kg-m, 22 Ib-ft)

TORQUE WRENCH
DIFFERENTIAL
INSPECTION TOOLS

07MAJ – PR90100

3. If preset torque is less than the service limit, replace the clutch discs with new ones.
NOTE: Adjust the thrust shim whenever the clutch

discs are replaced (see page 15-22).
ProCarManuals.com

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I



Clutch Disc, Clutch Plate

Replacement

NOTE: The clutch discs and clutch plates should be
replaced as a set.
1. Remove the clutch discs and clutch plates (see

page15-20).

2. Soak the clutch discs for five minutes in transmis-
sion oil.
3. Install the clutch discs, clutch plates, and a stan- dard shim.
NOTE: Position the 112 mm thrust Shim with the
thickness size mark facing away from the clutch

discs.

112 mm THRUST SHIM
Standard shim

A
B

C

D
E
F

G
J

Part Number

41261-PR8-000
41262-PR8-000
41263-PR8-000

41264-PR8-000
41265-PR8-000

41266-PR
8-000

41267-PR8-000

41268-PR8-000

41269-PR8-000

41270-PR8-000
Thickness

1.2 mm (0.0472 in)

1.4 mm (0.0551 in)
1.6 mm [0.0630 in)

1.8 mm (0.0709 in)

2.0 mm (0.0787 in)
2.2 mm (0,0866 in)
2.4 mm (0,0945 in)
2.6 mm (0.1024 in)
2.8 mm (0.1102 in)
3.0 mm (0.1181 in)


Measure

41.7– 41.9
mm

(1.642 – 1.650 In)
112 mm THRUST SHIM

FINAL

DRIVEN

GEAR

4. Install the differential housing.
NOTE: Tighten the bolts evenly in several steps,
then torque them in a crisscross pattern.
Torque: 40 N·m (4.0 kg-m. 29 Ib-ft)
5. Make sure the preset torque is within the standard (see page 15-18)
6. If preset torque is beyond the standard, replace the 112 mm thrust shim as necessary.ProCarManuals.com

Oil Seal

Removal

1. Remove the differential assembly.

2. Remove the oil seal from the transmission housing.

OIL SEAL

Replace.
TRANSMISSION

HOUSING

3. Remove the oil seal from the torque converter

housing.

OIL SEAL

Replace.
TORQUE CONVERTER

HOUSINGProCarManuals.com

Bearing Preload

Adjustment

NOTE: If any of the items listed below are replaced, the

bearing preload must be adjusted.

TRANSMISSION HOUSING

TORQUE CONVERTER HOUSING

DIFFERENTIAL

TAPERED ROLLER BEARING and OUTER RACE

75 mm THRUST SHIM

90 mm WASHER

OIL GUIDE RING

1. Remove the bearing outer race and 75 mm thrust

shim from the transmission housing by prying up

on the bearing outer race or by heating the housing

to about 212°F (100°C).

CAUTION: Do not reuse the thrust shim if the

outer race was pried out.

NOTE:

• If the outer race was removed by heating the

case, let the transmission cool to room tempera-

ture before adjusting the bearing preload.

• Do not heat the transmission housing in excess

of 212°F (100°C).

• Replace the bearing with a new one whenever

the outer race is replaced.

• Repeat on the torque converter side.ProCarManuals.com

2. Instal l th e standar d shi m an d bearin g oute r rac e in -
t o th e transmissio n housin g usin g th e specia l tool s
a s shown .
CAUTION : D o no t us e mor e tha n on e shi m to ad -
jus t th e bearin g preload .
NOTE:
• Instal l th e bearin g oute r rac e squarely .
• Chec k tha t ther e i s n o clearanc e betwee n th e
bearin g oute r race , shim , an d transmissio n
housing .
DRIVER07749-0010000 ATTACHMEN T72 x 7 5 m m07746-0010600
BEARIN GOUTERRACE
75 m m THRUS TSHIM
3. Lubricat e th e tapere d rolle r bearin g wit h transmis -
sio n fluid , the n instal l th e differential .
4 . Instal l th e transmissio n housing .
NOTE : D o no t instal l th e mainshaft , countershaft ,
revers e idl e gea r shaft , an d secondar y shaft .
Torque : 5 5 N- m (5. 5 kg-m , 4 0 Ib-ft )
5. Rotat e th e differentia l assembl y i n bot h direction s
t o sea t th e bearings .
7
5 m m THRUS T SHIM :
ProCarManuals.com

System Description

Major Components

The Electrical Power Steering system is composed of the following major components:

• A steering gearbox that converts rotary operation of the steering wheel into transverse operation via a rack and pinion

mechanism. Steering sensors and an actuating motor are incorporated.

• A control unit that computes the optimum amount of power assistance, taking into account steering torque, steering

speed, and vehicle speed. Self-diagnosis functions are included.

• A power unit that drives the motor according to the signals from the EPS control unit. A current sensor is built in to

give feedback information to the EPS control unit. Two relays shut off the power if a problem in the system occurs.

• The countershaft speed sensor on the automatic transmission or the differential speed sensor on the manual transmis-

sion sends a vehicle speed signal to the EPS control unit. Also the speedometer sends a vehicle speed signal to the EPS

control unit. The two signals are used as a double-check.ProCarManuals.com

System Operation

Manual Steering Operation

Steering wheel input rotates the pinion of the gearbox through a universal joint. Due to the rack and pinion mechanism,

the rotation of pinion is converted into a transverse motion at the rack, which steers the front wheels throught the tie-rods

and knuckles the same as an ordinary rack and pinion system.

Assisting Operation

In addition to the manual steering operation, the steering sensor on the pinion shaft transmits a signal to the EPS control

unit when it receives a steering input. The EPS control unit calculates an adequate motor control with addition of vehicle

speed signals. Based on the signal from the sensors, the EPS control unit drives the motor inside the gearbox. The torque

generated by the motor is transmitted to a ball screw, through gears, and converted into an assisting thrust in the axial

direction of rack. The assisting thrust acts in the steering direction and lessens the steering force required at the steering

wheel.

EPS CONTROL UNIT

RECIRCULATING

BALL SCREW

STEERING WHEEL
RACK

STEERING SENSOR

(Build in the rotation sensor

and torque sensor)

MOTOR

STEERING GEARBOXProCarManuals.com

System Description

Function and Operation

Steering Sensor

The steering sensor consists of a torque sensor, an

interface, and the rotation sensor.

Torque Sensor

The torque sensor converts steering torque input and its

direction to voltage signals, in conjunction with the

interface.

A torsional force caused by steering operation is con-

verted to an axial movement of a slider core. A variable

differential transformer is installed around the slider

core.

Within the transformer are three coils, a primary coil on

the inside, and two secondary coils, one for right turns

and one for left turns.

Alternating current is passed through the primary coil

when the system is energized. The amount of mutual

induction from the primary coil to the secondary coils

changes depending on the position of the slider coil.

The input shaft and the slider are one piece. Rotation of

the shaft moves the slider in a circular direction. The

pinion is turned via the torsion bar. The slider core is

installed on the pinion shaft on grooves, and turns with

the pinion shaft.

When there is little resistance, the input shaft torsion

bar, pinion shaft, and the slider core turn together to the

same angle. The slider core does not move up/down.
TORSION BAR

INPUT

SHAFT

INTERFACE

CIRCUIT

SPIRAL

GROOVE

ROTATION

SENSOR

GUIDE

PIN

TRANSFORMER

PINION GEAR

WING

When there is resistance on the input shaft (hard to steer situation), and the slider pin is turned at an angle by the steering

wheel, the torsion bar is twisted due to the resistance. Accordingly, the pinion shaft turns at a smaller angle. The differ-

ence in the turning angles changes the position of the slider pin in the groove, forcing the slider core upward or down-

ward, depending on the direction of the direction of the turn.

PRIMARY COIL

UPPER SECONDARY COIL

LOWER SECONDARY COIL

SLIDER
SLIDERProCarManuals.com