M/T Housing Mainshaft Thrust Clearance Adjustment

Special Tools Required
Mainshaft base (  07GAJ-PG20130)

Mainshaft holder (  07GAJ-PG20110)

1.Remove the 72 mm shim (A) and oil guide plate M from the transmission housing (B).


2.Thoroughly clean the spring washer (A) and washer (B) before installing them on the clutch housings side ball bearing (C). Note the installation direction of the spring washer.


3.Install the 3rd/4th synchro hub, the distance collar, the 5th synchro hub, the distance collar, and the ball bearing on the mainshaft.

NOTE: Refer to the mainshaft reassembly exploded view.

4.Install the mainshaft in the clutch housing.

5.Place the transmission housing over the mainshaft and onto the clutch housing.

6.Secure the clutch and transmission housings with several 8 mm bolts.

NOTE: It is not necessary to use sealing agent between the housing for this procedure.

7.Lightly tap on the mainshaft with a plastic hammer.

8.Attach the special tool to the mainshaft as follows:

  • Back-out the mainshaft holder bolt (A), and loosen the two hex bolts (B).
  • Fit the holder over the mainshaft so its lip is towards the transmission.
  • Align the mainshaft holder lip around the groove at the inside of the mainshaft splines, then tighten the hex bolts.


9.Fully seat the mainshaft by tapping its end with a plastic hammer.

10.Thread the mainshaft holder bolt in until it just contacts the wide surface of the mainshaft base.

11.Zero a dial gauge (A) on the end of the mainshaft.


12.Turn the mainshaft holder bolt (B) clockwise; stop turning when the dial gauge has reached its maximum movement. The reading on the dial gauge is the amount of mainshaft thrust clearance.

NOTE: Do not turn the mainshaft holder bolt more than 60 degrees after the needle of the dial gauge stops moving. Applying more pressure with the mainshaft holder bolt may damage the transmission.

13.If the reading is within the standard, the clearance is correct. If the reading is not within the standards, select the appropriate shim needed from the table, and recheck the thrust clearance.

Standard: 0.11-0.17 mm (0.004-0.007 in.) 

Measure reading: 1.93 mm (0.0759 in.) 

Subtract the total clearance measurement from the middle of the clearance standard 0.14 mm (0.0056 in.) 

1.93-0.14 mm = 1.79 mm (0.0704 in.) 

Select the shim closet to the amount calculated, for exaple the 1.80 mm (0.0709 in.) shim. 

14.With oil guide plate M and the appropriate size shim installed in the transmission housing, check the thrust clearance again to verify the clearance is within the standard.

72 mm Shim
 Part Number Thickness 
23931-P21-000 0.60 mm (0.0236 in.) 
23932-P21-000 0.63 mm (0.0248 in.) 
23933-P21-000 0.66 mm (0.0260 in.) 
23934-P21-000 0.69 mm (0.0271 in.) 
23935-P21-000 0.72 mm (0.0283 in.) 
23936-P21-000 0.75 mm (0.0295 in.) 
23937-P21-000 0.78 mm (0.0307 in.) 
23938-P21-000 0.81 mm (0.0319 in.) 
23939-P21-000 0.84 mm (0.0331 in.) 
23940-P21-000 0.87 mm (0.0343 in.) 
23941-P21-000 0.90 mm (0.0354 in.) 
23942-P21-000 0.93 mm (0.0366 in.) 
23943-P21-000 0.96 mm (0.0378 in.) 
23944-P21-000 0.99 mm (0.0390 in.) 
23945-P21-000 1.02 mm (0.0402 in.) 
23946-P21-000 1.05 mm (0.0413 in.) 
23947-P21-000 1.08 mm (0.0425 in.) 
23948-P21-000 1.11 mm (0.0437 in.) 
23949-P21-000 1.14 mm (0.0449 in.) 
23950-P21-000 1.17 mm (0.0461 in.) 
23951-P21-000 1.20 mm (0.0472 in.) 
23952-P21-000 1.23 mm (0.0484 in.) 
23953-P21-000 1.26 mm (0.0496 in.) 
23954-P21-000 1.29 mm (0.0508 in.) 
23955-P21-000 1.32 mm (0.0520 in.) 
23956-P21-000 1.35 mm (0.0531 in.) 
AA 23957-P21-000 1.38 mm (0.0543 in.) 
AB 23958-P21-000 1.41 mm (0.0555 in.) 
AC 23959-P21-000 1.44 mm (0.0567 in.) 
AD 23960-P21-000 1.47 mm (0.0579 in.) 
AE 23961-P21-000 1.50 mm (0.0591 in.) 
AF 23962-P21-000 1.53 mm (0.0602 in.) 
AG 23963-P21-000 1.56 mm (0.0614 in.) 
AH 23964-P21-000 1.59 mm (0.0626 in.) 
AI 23965-P21-000 1.62 mm (0.0638 in.) 
AJ 23966-P21-000 1.65 mm (0.0650 in.) 
AK 23967-P21-000 1.68 mm (0.0661 in.) 
AL 23968-P21-000 1.71 mm (0.0673 in.) 
AM 23969-P21-000 1.74 mm (0.0685 in.) 
AN 23970-P21-000 1.77 mm (0.0697 in.) 
AO 23971-P21-000 1.80 mm (0.0709 in.) 

 Part Number Thickness 
AP 23972-PPP-J00 1.83 mm (0.0720 in.) 
AQ 23973-PPP-J00 1.86 mm (0.0732 in.) 
AR 23974-PPP-J00 1.89 mm (0.0744 in.) 
AS 23975-PPP-J00 1.92 mm (0.0756 in.) 
AT 23976-PPP-J00 1.95 mm (0.0768 in.) 
AV 23977-PPP-J00 1.98 mm (0.0779 in.) 
AW 23978-PPP-J00 2.01 mm (0.0791 in.) 
AX 23979-PPP-J00 2.04 mm (0.0803 in.) 
AY 23980-PPP-J00 2.07 mm (0.0815 in.) 
AZ 23981-PPP-J00 2.10 mm (0.0826 in.) 
BA 23982-PPP-J00 2.13 mm (0.0838 in.) 
BB 23983-PPP-J00 2.16 mm (0.0850 in.) 
BC 23984-PPP-J00 2.19 mm (0.0862 in.) 
BD 23985-PPP-J00 2.22 mm (0.0874 in.) 
BE 23986-PPP-J00 2.25 mm (0.0886 in.)