Install the gearbox on a workbench or stand
Before disassembling, let's analyze the gearbox's faults
Main symptoms of gearbox faults and how to troubleshoot them
Noise or crackling when shifting gears:
- - check the oil level and its quality;
- - check the condition of the gearshift mechanism;
- - check the synchronizers and their hubs.
One or more gears do not engage:
- - check the oil level and its quality;
- - check the condition of the gearshift mechanism;
- - check the synchronizers;
- - check the gearshift forks and their retainers.
Spontaneous gear shifting out:
- - check the condition of the powertrain mounts;
- - check the condition of the gearshift mechanism;
- - check the synchronizers and their hubs;
- - check the gearshift forks and their retainers.
One or more gears are locked:
- - check the condition of the powertrain mounts;
- - check the condition of the gearshift mechanism;
- - check the synchronizers and their hubs;
- - check the gearshift forks and their retainers;
- - check the condition of the gear pinions.
Noise in the gearbox:
- - check the oil level and its quality;
- - check the condition of the gearbox bearings;
- - check the condition of the gears.
Remove the clutch slave cylinder mounting bolts (Fig. 1)
Fig. Fastening the clutch slave cylinder, NDO gearbox: 1 - pipeline fastening bolts, 2 - clutch cylinder fastening bolts.
Remove the gear selector mechanism thrust pin (1), the neutral sensor and reverse light switch (3), and the gear selector mechanism ball detent (2) (Figure 2).
Fig. Gearbox Disassembly: 1 - Gear selector thrust pin, 2 - Gear selector ball detent, 3 - Neutral sensor and reverse light switch, 4 - Gear selector mechanism mounting, 5 - Shift fork rod retainers, 6 - Cap.
Also, remove the mounting screws of the mechanism itself (shown with red arrows) and remove the mechanism assembly.
Remove the shift fork rod retainers (5) and the cap (6).
Remove the bolts securing the gearbox housing to the clutch housing.
Fig. Location of the secondary shaft retaining ring
Spread the secondary shaft bearing retaining ring (Fig. 3)
Next, remove the gearbox housing.
Remove the gear selector rod retainers (Fig. 4)
Fig. Gearbox assembly: 1a - large stopper and spring, 1b - smaller stopper and spring, 2 - reverse fork travel limiter, 3 - reverse gear rod and selector fork
After this, remove the reverse fork travel limiter (2) (Fig. 4)
Remove the reverse gear rod and selector fork (3)
Remove the two locking pins
Knock out, using a punch (or a valve, as used when disassembling the JH3 Gearbox), or if you have a tool as in Fig. 5, remove the pin securing the 5th and 6th gear shift fork.
Fig. 5: 1 - thrust half-ring
Remove the thrust half-rings of the 5th and 6th gear shift selector fork (1) and remove the "rod-fork" assembly.
Remove the push rod from the 5th and 6th gear shift rod and the two detent balls
Remove the thrust half-ring of the 3rd and 4th gear shift fork (see 1, Fig. 6).
Using the tool, remove the mounting pin of the 3rd and 4th gear shift selector fork.
Remove the 3rd and 4th gear shift rod assembly with the fork.
Remove the push rod from the 3rd and 4th gear shift rod.
Remove the mounting pin of the 1st and 2nd gear shift fork.
Remove the 1st and 2nd gear shift fork and rod assembly, and the reverse gear fork and rod assembly.
With the help of an assistant, remove the "input shaft - output shaft - reverse idler gear shaft" assembly.
