1991 ACURA NSX check transmission fluid

5. Install the side engine mount, then tighten the bolts
in the numbered sequence as shown ( - ),

12 x
1.26
mm

73 N·m
(7.3 kg-m,
53 Ib-ft)

Replace.
12 x
1.25
mm

95 N·m
(9.5 kg-m,
69 Ib-ft)

SIDE ENGINE

MOUNT

6. Tighten the transmission mount mounting bolt.

MOUNTING BOLT
12 x
1.25
mm

95 N·m (9.5 kg-m, 69 Ib-ft)
7. Tighten the rear mount mounting bolt.
MOUNTING BOLT

12 x
1.25
mm

77 N·m (7.7 kg-m, 56 Ib-ft)
Replace.

Check that the spring clip on the end of each
driveshaft clicks into place.
CAUTION: Use new spring clips.
Bleed air from the cooling system (see page 10-5).
Bleed air from the brake lines {see section 19).
Check the clutch pedal free play (see section 12).

Adjust the clutch guide assemblies when disas-

sembling clutch (see section 12).

Check that the transmission shifts into gear

smoothly.

Adjust the alternator belt (see section 23).
Adjust the A/C compressor belt (see section 22).
Clean battery posts and cable terminals with
sandpaper, assemble, then apply grease to pre-
vent corrosion.
Inspect for fuel leakage (see section 11). After assembling the fuel line parts, turn on
the ignition switch (do not operate the starter) so that the fuel pump operates for approxi-
mately two seconds and the fuel line pressu-
rizes. Repeat this operation two or three times
and check for fuel leakage at any point in the

fuel line.

Check and adjust wheel alignment (see section 18).

Refill the engine with engine oil (see page 8-4 ('91-'92
Models), ('93-Model),or ('94-'96 Models).

Refill the transmission with oil/fluid (see section

13 or
14).ProCarManuals.com

Description

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

automatic transmission which provides 4 speeds forward and 1 in 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 torque converter 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 three parallel shafts, the mainshaft, the countershaft, and the secondary shaft. The mainshaft is

in line with the engine crankshaft.

The mainshaft includes the clutches for 1st, and 4th, and gears for 3rd, 4th, Reverse and 1st (3rd gear is integral with

the mainshaft, while reverse gear is integral with 4th gear).

The countershaft includes the clutches for 1st-Hold and 3rd, and gears for 2nd, 3rd, 4th, Reverse and 1st.

The secondary shaft includes the 2nd clutch and gears for 2nd and 3rd.

The 4th and reverse gears can be locked to the countershaft at its center, providing 4th gear or Reverse, depending on

which way the selector is moved.

The gears on the mainshaft and secondary shaft 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 main-

shaft to the countershaft to provide , , , and

ELECTRONIC CONTROL

The electronic control system consists of the Transmission Control Module (TCM), sensors, a linear solenoid and 4

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

The TCM is located on the insulator center bulkhead, behind the driver's seat.

HYDRAULIC CONTROL

The valve bodies include the main valve body, secondary valve body, servo body, regulator valve body, throttle valve

body, lock-up valve body and the 2nd accumulator body.

They are bolted to the torque converter housing as an assembly.

The main valve body contains the manual valve, 1-2 shift valve, 2-3 shift valve, 3-4 shift valve, relief valve, one-way

relief valve and oil pump gears.

The secondary valve body contains the 3-2 kick-down valve, CPC (clutch pressure control) valve, 2nd orifice control

valve, 3rd orifice control valve, modulator valve, 4th exhaust valve, servo control valve, 2nd exhaust valve and 4-3 kick-

down valve.

The servo body contains the accumulator pistons and servo valve. The throttle valve body includes the throttle valve B

which is bolted onto the servo body.

The regulator valve body contains the pressure regulator valve, lock-up control valve and cooler relief valve. Fluid from

the regulator passes through the manual valve to the various control valves.

The lock-up valve body contains the lock-up timing B valve and lock-up shift valve. The 2nd accumulator body contains

the accumulator pistons and limited slip differential (LSD) relief valve.

The torque converter check valve is located in the torque converter housing, under the main valve body.

The 1st, 1st-hold, 3rd and 4th clutches receive oil from their respective feed pipes.

SHIFT CONTROL MECHANISM

Input from various sensors located throughout the car determines which shift control solenoid valve the TCM will ac-

tivate. 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 and position in 2nd, 3rd and 4th, pressurized fluid is drained from the back of the torque converter

through an oil 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 TCM optimizes the

timing of the lock-up mechaism.

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. The lock-up control solenoid valves

A and B are mounted on the torque converter housing, and are controlled by the TCM.

(cont'd)ProCarManuals.com

As the engine turns, the oil pump also starts to operate. Automatic transmission fluid (ATF) is drawn from (99) and

discharged into (1). Then, ATF pressure is controled by the regulator valve and becomes line pressure (1). The torque

converter inlet pressure (92) enters (94) of torque converter through the orifice and discharges into (90).

The torque converter check valve prevents the torque converter pressure from rising.

Under this condition, the hydraulic pressure is not applied to the clutches.

(cont'd)
positionProCarManuals.com

Fluid Level

Checking/Changing

Checking

NOTE: Check the fluid level with the engine at nor-

mal operating temperature (the cooling fan comes

on).

1. Park the car on level ground. Turn off the engine.

2. Remove the dipstick (yellow loop) from the

transmission, and wipe it with a clean cloth.

NOTE: Check the fluid level for to 90 seconds

from 60 seconds after the engine had shut off.

3. Insert the dipstick into the transmission.

4. Remove the dipstick, and check the fluid level. It

should be between the upper and lower marks.

5. If the level is below the lower mark, add fluid into

the tube to bring it to the upper mark. Use Honda

Premium Formula Automatic Transmission Fluid or

an equivalent DEXRON® II Automatic Transmission

Fluid (ATF) only.

6. Insert the dipstick back into the transmission.

UPPER

LOWER

DIPSTICK

(YELLOW LOOP)

DRAIN PLUG

50 N·m (5.0 kg-m, 36 Ib-ft)

SEALING WASHER

Replace.
Changing

1. Bring the transmission up to operating temperature

by driving the car. Park the car on level ground, turn

the engine off, then remove drain plug.

2. Reinstall the drain plug with a new washer, then refill

the transmission to the full mark on the dipstick.

Automatic Transmission Fluid Capacity:

2.9 (3.1 US qt., 2.6 Imp. qt.) at change

7.0 (7.4 US qt., 6.2 Imp. qt.) after overhaul

6.3 (6.7 US qt., 5.5 Imp. qt.) after overhaul

with new torque

converter.ProCarManuals.com

Transmission
Removal
Make sure lifts are placed properly, and

hoist brackets are attached to correct position (see sec-

tion 1).
CAUTION: Use fender covers to avoid damaging painted

surfaces.

1. Check and record the rear camber. (see section 18.)
2. Disconnect the battery negative (-) first, and positive (+) cable from the battery.
3. Drain automatic transmission fluid (ATF). Reinstall the drain plug with a new washer.
NOTE: Removing the ATF level gauge will allow the
ATF to drain more rapidly. 4. Remove the strut bar.
5. Remove the air cleaner housing.
6. Remove the connectors from the control box and remove the control box (see section 11).
CAUTION: Do not remove the vacuum tubes from
the control box.
7. Remove the wire harness holder, disconnect the vehicle speed sensor (VSS) wire connectors,
solenoid valve wire connectors, starter motor
cables and transmission ground cable.
8. Remove the ATF cooler as it is connected by the
hoses.

CAUTION: Do not remove the hoses from the ATF

cooler.

9. Remove the starter motor mounting bolts, then remove the starter motor.
10. Remove the transmission housing bolts and the transmission mounting bolts.
MAINSHAFT SPEED SENSOR
CONNECTOR
LOCK-UP CONTROL
SOLENOID VALVE
CONNECTOR
STARTER MOTOR
TRANSMISSION

HOUSING BOLTS
CONTROL BOX
STARTER MOTOR
STARTER MOTOR
MOUNTING BOLT
ATF COOLER
ATF COOLER FILTER/GASKET Replace.

VSS

CONNECTOR
COUNTERSHAFT SPEED SENSOR
CONNECTOR
LINEAR SOLENOID
CONNECTOR

SHIFT CONTROL

SOLENOID VALVE
CONNECTOR
GROUND CABLE
TRANSMISSION

MOUNTING BOLTS
TRANSMISSION

HANGER
Corrosion resistant bolt/nut

CABLEProCarManuals.com

Transmission

Installation (cont'd)
27. Install the 3 transmission mounting bolts, and the 2 transmission housing mounting bolts.
28. Install the starter motor and tighten the starter motor mounting bolts.
29. Install the ATF cooler.
30. Connect the transmission ground cable, starter motor cable, solenoid valve wire connectors and vehicle
speed sensor (VSS) wire connectors.
31. Install the control box and connect the control box connectors.
32. Install the air cleaner housing.
33. Install the strut bar.
TORQUE: 39 N .
m (3.9 kg-m, 28 Ib-ft)
Corrosion resistant bolt/nut 34. Refill the transmission with ATF.
35. Connect the battery positive (+) and negative (-) ca- ble to the battery.
36. Inspect the rear camber (see section 18).
37. Start the engine. Set the parking brake, and shift the transmission through all gears three times. Check forproper shift cable adjustment.
38. Check the ignition timing (see section 23).
39. Let the engine reach normal operating temperature (the cooling fan comeson) with the transmission in or position, then turn it off and check the
fluid level.
40. Road test as described on page 14-88.
TRANSMISSION HOUSING MOUNTING BOLT
12 x
1.25
mm

75 N .
m (7.5 kg-m, 54 Ib-ft)
CONTROL BOX

8x1.25 mm
18 N .
m
(1.8 kg-m,
13 Ib-ft)
TRANSMISSION MOUNTING BOLT
10 x 1.25mm

60 N .
m (6.0 kg-m, 43 Ib-ft)
STARTER MOTOR
MOUNTING BOLT
12 x 1.25mm

75 N .
m
(7.5 kg-m,
54 Ib-ft)ProCarManuals.com

Modulator/Solenoid Unit

Solenoid Leak Test

1. Disconnect the 6-P inspection connector (PNK) from the connector cover located under the glovebox and connect the inspection connector to the
ALB checker.

ANTI-LOCK BRAKE SYSTEM
INDICATOR LIGHT

CONNECTOR

COVER

ALB CHECKER

07HAJ - SG00100 or
07HAJ - SG0010B (US)

07HAJ - SG00200 (Canada)
6-P INSPECTION

CONNECTOR

CAUTION: Place the vehicle on level ground with
the wheels blocked. Put the transmission in neutral
for manual transmission models, and in P for automatic transmission models.
2. Remove the modulator reservoir filter, then fill the modulator reservoir to the MAX level.
NOTE: Do not reuse aerated brake fluid that has
been bled from the power unit.
3. Bleed high pressure fluid from the maintenance bleeder with the special tool.
BLEEDER T-WRENCH

07HAA-SG00100
or

07HAA-SG00101

SOLENOID HEAD
MAINTENANCE
BLEEDER

8 x
1.25
mm
5.5 N·m
(0.55 kg-m,

4.0 Ib-ft)

POWER

UNIT

ACCUMULATOR/
PRESSURE SWITCH
If you can feel back fluid coming from the return
tube, one of the solenoids is leaking. Go to Solenoid Flushing.If you can feel brake fluid coming from the return
tube, one of the solenoids is leaking. Go to step
7.

If you can't feel brake fluid coming from the return tube, the solenoids are OK.
Reinstall the modulator reservoir filter and refill
the reservoir to the MAX level.
7. Bleed high-pressure fluid from the maintenance
bleeder with the special tool, then run through

modes 3 and 6 with the ALB checker. Repeat this

three or four times.

8. Repeat steps 5 and 6. If the solenoid leakage has stopped, reinstall the
modulator reservoir filter and refill the reservoir
to the MAX level. If one of the solenoids is still leaking, replace the
modulator/solenoid
unit.
SOLENOID

RETURN

TUBE
PUMP

SUPPLY

BRAKE

FLUID
SOLENOID RETURN

TUBE
Feel for brake

fluid here.

4. Start the engine and release the parking brake.
5. Turn the Mode Selector to 1 and press the Start Test button.
6. While the pump is running, place your finger over the top of the solenoid return tube in the modulator
reservoir.ProCarManuals.com

Bleeding

Air Bleeding with ALB Checker
1. Disconnect the 6-P inspection connecotor (PNK) from the connector cover located under the glovebox and connect the inspection connector to the
ALB checker.
ANTI-LOCK BRAKE SYSTEM
INDICATOR LIGHT

CONNECTOR

COVER

ALB CHECKER

07HAJ - SG00100 or

07HAJ - SG0010B (US)

or

07HAJ-SG00200 (Canada)
6-P INSPECTION

CONNECTOR

CAUTION: Place the vehicle on level ground with
the wheels blocked. Put the transmission in neutral
for manual transmission models, and in P for automatic transmission models.
2. Fill the modulator reservoir to the MAX level.
NOTE: Do not reuse aerated brake fluid that has
been bled from the power unit.
3. Bleed high pressure fluid from the maintenance bleeder with the special tool.
BLEEDER T-WRENCH

07HAA-SG00100

or

07HAA-SG00101

SOLENOID HEAD

ACCUMULATOR/
PRESSURE SWITCH
POWER

UNIT
MAINTENANCE

BLEEDER

8 x
1.25
mm
5.5 N·m
(0.55 kg-m,
4.0 Ib-ft) 7. Install the reservoir cap.

8. Check the anti-lock brake system function in all

modes by using the ALB checker.
MAX

RESERVOIR

CAP

4. Start the engine and release the parking brake.
NOTE: Depress the brake pedal firmly while test in pro-

gress light in ON.

5. There should be at least two strong kickbacks. If not, repeat steps 2 through 5, as necessary.
6. Fill the modulator reservoir up to the MAX level.ProCarManuals.com