1991 ACURA NSX Service Repair Manual

Change Holder Assembly, Shift Fork

Clearance Inspection

1. Measure the clearance between the shift piece and

shift arm.

Standard: 0.05—0.25 mm

(0.002-0.010
in)

Service Limit: 0.5 mm (0.020 in)

SHIFT ARM
SHIFT PIECE

2. If the clearance exceeds the service limit, measure

the width of the shift arm.

Standard:
12.9-13.0
mm
(0.508-0.512
in)

SHIFT ARM

If the width of the shift arm is less than the stan-

dard, replace the shift arm with a new one.

If the width of the shift arm is within the standard,

replace the shift piece with a new one.
3. Measure the clearance between the interlock and

select arm.

Standard:
0.03-0.15
mm
(0.001
-
0.006
in)

INTERLOCK

SELECT ARM

4. If the clearance exceeds the standard, measure the

width of the interlock finger.

Standard: 11.95 - 12.00 mm

(0.470-0.472 in)

INTERLOCK

If the width of the interlock is less than the stan-

dard, replace the interlock with a new one.

If the width of the interlock is within the standard,

replace the select arm with a new one.ProCarManuals.com

5. Measure the clearance between the shift fork, the

5th/reverse shift piece and shift piece.

Standard:
0.2-0.5
mm

(0.008-0.020
in)

Service Limit: 0.6 mm (0.024 in)

1ST/2ND SHIFT FORK

5TH/REVERSE

SHIFT PIECE

6. If the
clearance exceeds
the
service
limit,
measure

the width of the shift piece.

Standard: 11.9 - 12.0 mm (0.469-0.472 in)

SHIFT PIECE

If the width of the shift piece is less than the stan-

dard, replace the shift piece with a new one.

If the width of the shift piece is within the standard,

replace the 5th/reverse shift piece or shift forks

with a new one.
3RD/4TH

SHIFT FORK

SHIFT PIECEProCarManuals.com

Shift Fork, Synchro

Sleeve

Clearance Inspection

1. Measure the clearance between each shift fork and

its matching synchro sleeve.

Standard:
0.45-0.65
mm

(0.018-0.026 in)

Service Limit: 1.0 mm (0.039 in)

SYNCHRO

SLEEVE

SHIFT FORK

2. If the clearance exceeds the service limit, measure

the width of the shift fork fingers.

Standard:

1st/2nd
Shift
Fork:
8.9-9.0
mm

(0.350-0.354 in)

3rd/4th
Shift
Fork:
7.4-7.5
mm

(0.291 - 0.295 in)

5th Shift Fork: 6.4—6.5 mm

(0.252-0.256 in)

SHIFT FORK

If the width of the shift fork fingers is less than the

standard, replace the shift fork with a new one.

If the width of the shift fork fingers is within the

standard, replace the synchro sleeve with a new

one.

NOTE: The synchro sleeve and synchro hub

should be replaced as a set.ProCarManuals.com

Mainshaft Assembly

Clearance Inspection

1. Measure the clearance between 2nd and 3rd gears.

Standard: 0.06 — 0.21 mm

(0.002-0.008
in)

Service Limit: 0.3 mm (0.012 in)

2ND GEAR

3RD GEAR

2. If the clearance exceeds the service limit, measure

the thickness of 3rd gear.

Standard: 35.92 — 35.97 mm

(1.414-1.416 in)

Service Limit: 35.80 mm (1.409 in)

3RD GEAR

If the thickness of 3rd gear is less than the service

limit, replace 3rd gear with a new one.

If the thickness of 3rd gear is within the service

limit, replace the 3rd/4th synchro hub with a new

one.
3. Measure the clearance between 4th gear and the

spacer collar.

Standard: 0.06—0.21 mm

(0.002-0.008
in)

Service Limit: 0.3 mm (0.012 in)

4TH GEAR

5TH GEAR

4. If the clearance exceeds the service limit, measure

distance on the spacer collar.

Standard: 29.53 — 29.58 mm

(1.163-1.165 in)

Service Limit: 29.51 mm (1.162 in)

SPACER

COLLAR
4TH GEAR

"SIDE

5. If distance is less than the service limit, replace

the spacer collar with a new one.

If
distance
is
within
the
service
limit,
measure

the thickness of 4th gear.

Standard: 35.92-35.97 mm

(1.414-1.416 in)

Service Limit: 35.80 mm (1.409 in)

If the thickness of 4th gear is less than the service

limit,
replace
4th
gear
with
a new
one.

If the thickness of 4th gear is within the service

limit, replace the 3rd/4th synchro hub with a new

one.
4TH

GEARProCarManuals.com

6. Measure the clearance between the spacer collar

and 5th gear.

Standard: 0.06—0.21 mm

(0.002-0.008
in)

Service Limit: 0.3 mm (0.012 in)

4TH GEAR

5TH GEAR

7. If the clearance exceeds the service limit, measure

distance on the spacer collar.

Standard: 28.53—28.58 mm

(1.123-1.125 in)

Service Limit: 28.51 mm (1.122 in)

5TH GEAR

SIDE
SPACER

COLLAR

8. If distance is less than the service limit, replace

the spacer collar with a new one.

If distance is within the service limit, measure

thickness of 5th gear.

Standard: 34.92-34.97 mm

(1.375-1.377 in)

Service Limit: 34.80 mm (1.370 in)

5TH GEAR

If the thickness of 5th gear is less than the service

limit, replace 5th gear with a new one.

If the thickness of 5th gear is within the service

limit, replace the 5th synchro hub with a new one.ProCarManuals.com

Shift Fork Assembly

Disassembly/Reassembly

NOTE:

• Be careful not to lose the 5th shift fork steel ball.

• Install the spring pins so their grooves are 180° apart.

Prior to reassembling, clean all the parts in solvent, dry them, and apply lubricant to any contact surfaces.

Disassembly: Remove the 3 mm spring pin and 5 mm spring pin.

Reassembly: Install the 5 mm spring pin first, then install the 3 mm spring pin.

5TH/REVERSE SHIFT

FORK SHAFT
3RD/4TH SHIFT FORK

SHAFT COLLAR

1ST/2ND SHIFT

FORK SHAFT

5TH SHIFT FORK

SPRING WASHER

8 x 1.0 mm

SPECIAL BOLT

32 N-m (3.2 kg-m, 23 Ib-ft)
3RD/4TH SHIFT FORK

3RD/4TH SHIFT

FORK SHAFT

5 x 25 mm

SPRING PIN

Replace.
1ST/2ND SHIFT FORK

3 x 25 mm

SPRING PIN

Replace.

5 x 25 mm

SPRING PIN

Replace.

Drive to the

surface end.
5TH/REVERSE

SHIFT PIECE

3 x 25 mm

SPRING PIN

Replace.
STEEL

BALL (5/16 in)ProCarManuals.com

Mainshaft Assembl y
Index
NOTE : Th e 3rd/4t h an d 5t h synchr o hub s ar e installe d wit h a press .
Prior t o reassembling , clea n al l th e part s i n solvent , dr y them , an d appl y lubrican t t o an y contac t surfaces .
The 3rd/4t h an d 5t h synchr o hubs , however , shoul d b e installe d wit h a pres s befor e lubricatin g them .
3RD/4T H SYNCHR O HU B
SYNCHR O SPRIN G
SYNCHR O RIN G
Inspection , pag e 13-3 5
3RD GEA R
Measurement , pag e
13-24
43 x 49 x 29. 5 mmNEEDL E BEARING SInspect fo r wea r an d operatio n
MAINSHAF TInspection, pag e 13-2 6
BALL BEARIN GInspect fo r wea r an d operation .
BALL BEARIN GInspect fo r wea r an d operation .
5TH SYNCHR O SLEEV E
Inspection , pag e 13-3 6
5TH SYNCHRO HUB
SYNCHR O SPRIN G
SYNCHRO RINGInspection , pag e 13-3 5
5T H GEA R
Measurement , pag e 13-2 5
42 x 47 x 29 m mNEEDL E BEARIN GInspect fo r wea r an d operation .
SPACER COLLA R
Inspection , pag e 13-2 4
4T H GEA R
Measurement , pag e 13-2 4
SYNCHR O RIN G
Inspection , pag e 13-3 5
SYNCHR O SPRIN G
3RD/4T H SYNCHR O SLEEV E
Inspection , pag e 13-3 6
STOPPE R
ProCarManuals.com

Disassembly

1. Remove the ball bearing using a bearing puller as

shown.

Clutch housing side:

Transmission housing side:
BEARING PULLER

(Commercially

available)

BALL BEARING

BEARING

SEPARATOR,

0-4 1/2 in.

(Commercially

available)

BEARING PULLER

(Commercially

available)

BALL BEARING

BEARING

SEPARATOR,

0-4 1/2 in.

(Commercially

available)ProCarManuals.com