Page 897 - Workshop Manual - Aumark (BJ1051)

31A-17
Transmission (646b/651b)-transmission assembly

16. Detect the internal diameters of all the secondary-
shifting gears
(a). Measure the internal diameters of all the
secondary-shifting gears.
Internal diameter
Gear position
Standard Limit
Sixth-shifting gear
646B 40 mm 40.050~40.075
mm

651B
Fourth-shifting gear
646B 58 mm 58.01~58.04 mm

651B
Third-shifting gear
646B 64 mm 64.01~64.04 mm
651B
Second-shifting
gear 646B 71 mm 71.01~71.04 mm
651B
First-shifting gear 64 mm 64.01~64.04mm
646B 70 mm 71.01~71.04 mm
651B
Reverse gear 646B 0.020 ~ 58.01~58.04 mm
651B 0.069 mm

If the value of the internal diameter is beyond the limit
value, replace the gears.
17. Detect the copper ring of synchronizer
(a). Inspect whether there is wear and damage.
(b). Press the copper ring of synchronizer towards the
gear and turn towards the same direction, inspect the
locking effect. If the locking is not enough, apply a
layer of high-quality grinding paster on the contact
surfaces of the copper ring and the gear of the
synchronizer and polish slightly.
Notice:
Make sure to clean the grinding paster after polishing.
(c). Inspect the locking effect of the synchronizer copper
ring again. 31A
(d). If the locking effect is still not ideal, detect the
clearance between the synchronizer ring and the gear.

(e). Measure the clearance between the gear and the
copper ring of synchronizer.

Position of copper Clearance
ring Standard Limit
Third-shifting and
fourth-shifting 646B 1.05~2.25 mm 2.75 mm
651B

Fifth-shifting and
sixth-shifting 646B 0.6~0.8 mm 1.3 mm
651B

If the actual value is beyond the limit value, replace with a
new copper ring of synchronizer.

Page 897