1) Clean all components thoroughly, inspect them for
any abnormality and replace with new ones as
2) Check clearance "a" between synchronizer ring (2)
and gear (1), 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.
Clearance "a" between synchronizer ring and
Standard: 1.0 – 1.4 mm (0.040 – 0.055 in.)
Service limit: 0.5 mm (0.020 in.)
Key slot width "b"
Standard: 10.0 – 10.2 mm (0.394 – 0.401 in.)
Limit: 10.45 mm (0.411 in.)
3) To ensure lubrication of input shaft (1), air blow oil
holes (2) and make sure that they are free from any
4) Fit high speed synchronizer sleeve (4) to hub (3),
insert 3 keys (2) in it and then set springs (1) as
shown in figure.
• No specific direction is assigned to high
speed synchronizer sleeve or each key but
it is assigned as assembly.
• Size of high speed synchronizer sleeve,
hub, keys and springs are the smaller than
those of low speed one.
Synchronizer key installation position
A = B
[A]: 4th gear side
C: Left side (Short flange)
D: Key way
E: Projecting end
5) Drive in right bering (1) to input shaft (2) using
special tool and hydraulic press.