Main Shaft and Countershaft
Main Shaft Disassembly1) After removing needle bearing for input shaft at the front end of main shaft, pull out high speed sleeve from its hub (3) and remove 3 synchronizer keys.
2) Remove circlip in front of hub (3) and pull off hub (3) with special tool (A), then take out synchronizer springs.
Special tool (A): 09913-61510
3) Remove 3rd synchronizer ring (2), 3rd gear (1) and needle bearing.
NOTE: High speed sleeve-hub assembly, synchronizer ring and 3rd gear (1) can be removed all at once by using puller and hydraulic press.
4) Remove circlip in the rear part of main shaft (1) and pull off rear bearing (2) with bearing puller (3) and press.
5) Remove thrust washer and steel ball and then remove 5th gear, synchronizer ring and needle bearing
6) Pull out reverse sleeve from its hub (2) and remove 3 synchronizer keys.
7) Remove circlip and pull off reverse hub (2) from main shaft (1) with bearing puller (3) and press, then take out synchronizer springs.
NOTE: It is also possible to remove reverse sleeve-hub as assembly and reverse gear all at once by using puller and press, attar removing circlip.
8) Remove main shaft reverse gear and needle bearing by hand.
9) Using bearing puller (4) and press, remove reverse gear bush (2) and bearing washer (3) from main shaft (1).
NOTE: During above work, watch out for steel ball which will come out from inside of washer so as not to lose it.
CAUTION: Do not attempt to pull out bearing, washer (3) and bush (2) all together at once. Steel ball would stop bearing and cause damage to it.
10) Pull off bearing (1) with bearing puller (2) and press.
11) Remove the following in that order: bearing washer, steel ball, low gear, low synchronizer, needle bearing and low gear bush (1).
12) Using bearing puller (4) and press, pull out low speed sleeve and hub assembly (2), 2nd gear (3) and 2nd synchronizer ring all together.
NOTE: If bush can't be pulled out by hand at Stop 11), pull off sleeve and hub together by using press.
13) Remove sleeve from hub and then take off synchronizer keys and springs.
Countershaft and Main Shaft Inner Parts Inspection
Check for the following items.
^ Check tooth surface of gear and rotation of bearing and replace with new one if necessary. As long as no abnormal condition such as noise exists before removal, replacement is unnecessary.
^ Inspect needle bearings and needle contacting surfaces (rotating surfaces) and replace with new ones as required.
NOTE: Should abnormal noise be heard before disassembly, it is necessary to carefully check needle contacting surface inside of each gear besides those parts shown in figure.
^ Check clearance "a" between synchronizer ring and gear, key slot width "b" in synchronizer ring and each chamfered tooth of gear and synchronizer ring and replace with new one, if necessary. Also, check gear tooth.
^ Check chamfered part of each sleeve for damage and excessive wear, and replace as necessary. Using feeler gauge, check clearance "c" between sleeve (1) and shifter fork (2) and replace parts if necessary.
^ Check each synchronizer key and synchronizer spring and replace as necessary.
^ Check splined portions and replace parts if excessive wear are found.
Low and Reverse Scissors Gear Assemblies Inspection
Check for the following items
^ Match mark (3) provided for reassembly should be almost at such position as shown in figure.
^ Try to turn scissors gear against main shaft low (and reverse) gear. It should feel light when turned in "A" direction but heavy when turned in "B" direction.
^ Play of scissors gear against main shaft low (or reverse) gear in "A" - "B" direction should be about half of tooth width as shown in figure,
If any faulty condition is noted, remove snap ring, open up assembly unit and check that all components are installed at proper positions. If all components are positioned properly and yet faulty condition exists, replace the low (reverse) gear assembly.
Main Shaft Assembly
NOTE:
^ Before assembly, wash each part and apply specified gear oil to sliding faces of bearing and gear.
^ Use new circlips on shaft for reinstallation. Don't reuse used circlips.
1) Fit sleeve to low speed hub (1), place 3 synchronizer keys (4) in it and set synchronizer spring (3). Refer to figure for proper installing direction of hub (1), sleeve (2) and springs (3). Synchronizer key (4) has no specific direction for installation.
NOTE: When installing each synchronizer spring, insert its hooked end to hub hole and put it toward right.
2) Install needle bearing (2), 2nd gear (3) and 2nd synchronizer ring to main shaft (1).
3) Press-fit sleeve and hub assembly (2) onto main shaft (1) with press (3).
4) Insert low gear bush (1) and set synchronizer ring (3), needle bearing (2) and low gear (4).
5) Set steel ball (1) and washer (2).
6) Using special tool (B) and press, press-fit bearing (1).
7) Fit sleeve (4) to reverse hub (3), place 3 synchronizer keys (2) in it and then set synchronizer springs (1). Refer to figure for proper installing direction of hub (3), sleeve (4) and springs (1). Also, note that key (2) has specific installing direction.
8) Set steel ball and bearing washer (2) and insert reverse gear bush (3), needle bearing (4) and reverse gear (5).
9) Press-fit reverse sleeve and hub assembly (1) with special tool (B) and press.
10) After setting large circlip (2), install 5th speed synchronizer ring, needle bearing, 5th gear (4), steel ball (5) and washer (6).
NOTE: Washer should be installed with its oil slot side facing gear.
11) Press-fit bearing (1) with special tool (B) and press.
12) Fit small circlip.
13) Fit sleeve (4) to high speed hub (3), place 3 synchronizer keys (2) and set synchronizer springs (1) as shown in figure. Neither sleeve nor key has specific installing direction.
14) Install needle bearing, 3rd gear (3) and 3rd synchronizer ring (2). Then using special tool (C) and press, press-fit high speed sleeve and hub assembly (1) onto shaft.
15) Fit large circlip.
16) Install needle bearing.
Countershaft Assembly
1) Install pin (6), friction gear (5), friction gear spring (4), friction gear retainer (3) and circlip (2) to counter shaft (1) in that order.
2) Press-fit front bearing (1) and fit circlip.
3) With shaft inserted into case, install center bearing outer race (1) on it and then press-fit counter shaft (2) by using special tool and hammer. Meanwhile case should be supported on wood blocks.
4) Press-fit reverse gear (1) and then 5th gear (2).
NOTE: When press-fitting, hold counter shaft (4) as shown in figure with its front end set on special tool.
5) Install bearing plate (1) applying thread lock cement "A" to their thread part of bolts.
6) Install reverse idle gear (3) together with needle bearing (2) and thrust washer (1) on reverse idle gear shaft (4) and fix them with bolt (5) from outside of case.
NOTE: Be sure to use aluminum washer for bolt.
7) After press-fitting counter shaft rear bearing (1) to counter shaft, make sure to fit circlip securely.
8) Fit circlip (1) around bearing (2) and check to make sure that circlip just contacts with case surface.