197 

 

No. 146 Gear shifting lever swinging, hard to shift   

Malfunction Causes 

Solution 

Gear shifting lever loosens, shifting 
incorrect;  

Check nylon cover of gear shifting lever is unusually worn; if 
so, replace it;   

Gear shifting 
lever swinging, 
hard to shift 

Gap between shift ball head and swing lever 
too large, shifting incorrect; 

Check shift ball head and swing lever loosen; if so, replace it;

 

Gear shifting lever swinging, hard to shift 

Shift bar loosens, shifting incorrect 

Clearance between shift ball head and swing 

lever too large, shifting incorrect 

Repaiar or replace 

Repair 

Normal 

Abnormal 

Abnormal 

 
 

 

 

198 

 

No. 147 Sounding when releasing throttle of third, fourth gears and decelerating   

Malfunction Causes 

Solution 

Transmission oil quality, quantity   

Check viscosity of transmission oil is too small, and quantity is 
too little. Fill API GL-4 

SAE 80W-85, and oil level shall be 

flush with lower plane of oil filler.   

Gear clearance of third, fourth gear too large

Check driving gear and driven gear of third, fourth gear. 
Abrasion of tooth shall not exceed 30% of original tooth length, 
and abrasion of its depth no more than 0.5mm. Meshing area 
of gear shall be no less than 2/3 of working surface; meshing 
clearance no larger than 0.5mm; change gear pair if too large; 

Bearing with abnormal sound(major 

inspection) 

Mainly check abrasion of bearing of input shaft 6205 (without 
slot), output shaft 6305 (with slot). And the bearing shall be 
operating without abnormal sound or jamming. Ball track with 
the bearing shall not be fallen. Shaking with hands shall be 
without loosening sound. In case of above-mentioned 
problems, change bearing;   

Large play of one shaft 

If play of one shaft is too large, check bearing of one shaft is 
loosening; replace it if so;   

Sounding when 
releasing throttle 
of third, fourth 
gears and 
decelerating 

Synchronizer malfunction 

Check synchronizer of third, fourth gear is loosening; replace it 
if so; 

 

Sounding when releasing throttle of third, 

fourth gears and decelerating 

Transmission oil quality, quantity 

Gear clearance of third, fourth gear too 

large 

Bearing with unusual noise 

Large play of one shaft 

Synchronizer malfunction 

Repair 

Repaiar or replace 

Fill up accordingly 

Repair 

Replace 

Normal 

Abnormal 

Abnormal 

Abnormal 

Abnormal 

Abnormal 

Normal 

Normal 

Normal 

 
 

 

 

199 

No. 148 Fifth gear not easily shifted up   

Malfunction Causes 

Solution 

Shift lever malfunction 

Check gear shifting lever is bent or deformed, rubber sleeve is 
aging, loosening   

Transmission shift operation 
mechanism malfunction   

Check swing link support is worn, loosening or deformed, and shift 
shaft and device of fifth gear is smoothly put into gear; if not, replace 
swing link support assembly; check shift fork of fifth gear is vertical 
to shift fork shaft; if not, replace shift fork of fifth gear;   

Synchronizer assembly of fifth gear 
malfunction 

1. Toothed ring of fifth-gear synchronizer is excessively worn, and 
clearance of toothed ring pressed at gear no less than 0.5mm, with 
specified value between 0.85-1.45; area of joint face of fifth-gear 
synchronizer and gear shall be larger than 80%; replace 
synchronizer ring if not; 
2. Check height of slide block of synchronizer is no less than 5mm; 
replace slide block of synchronizer if less than 5mm; 
3. Check synchronizer hub and cover is too loosening or too 
tightening. Hub shall be assembled within the cover freely. Joint part 
of cover and gear shall be triangular. Replace synchronizer 
assembly if damaged, worn, or its edge angle turning round; 

Fifth gear not 
easily shifted up 

Transmission input, output shaft 
fifth-gear malfunction 

Replace transmission input, output shaft fifth-gear; 

 

 
 

 

 

200 

 

No. 149 Fifth gear, first gear blocks, relieved only when the vehicle stops   

Malfunction  

Causes 

Solution  

 Gear shifting lever malfunction

⑴

 

 

 Check gear shifting lever is bent or deformed, rubber cover 

①

is aging or loosening;   

Clutch not fully separated 

⑵

 

 Check free clearance of pedal is at 1

①

-3mm; clearance of 

bearing and pressure plate is better at 2-3mm; if too large, 
adjust accordingly; (empirical data) 

 If clutch spring is too soft, replace it; 

②

 

 If clutch friction disk is excessively worn, replace it;

③

 

 Check clutch plate and flywheel surface is bent, deformed 

④
(replace it if amount of deformation is above 0.5mm); 

Fifth gear, first 
gear blocks, 
relieved only 
when the vehivle 
stops 

Transmission inner malfunction

⑶

 

 Check swing link support, right

①

-angle shaft is deformed, 

loosening. Right angle is 90 degree by visual measurement, 
and if bending angle diminishes, replace swing link support;   

 Check fifth

②

-gear synchronizer, and cover within hub is too 

loosening and slanted around; if too loosening, replace 
synchronizer assembly;   

 Check height of slide block of synchronizer; if less than 

③
5mm, replace slide block;   

 Check soldered tooth of driven gear of one gear is too

④

 far 

from engaging tooth of another gear, and clutch collar may be 
too deep inside. Press soldered tooth by forcing machine; 

Check clearance between rear end plate of fifth gear 

synchronizer and hub is too large; after fifth-gear is put, slide 
block turns up, and blocks when to be relived. clearance shall 
be within 2mm; if too large, replace rear end plate; 

 

Fifth gear not easily shifted up 

Shift lever 

Transmission shift operation 

mechanism 

Fifth-gear synchronizer 

Transmission input, output shaft 

fifth-gear 

Repair 

Replace 

Repair 

Replace 

Normal 

Abnormal 

Normal 

Normal 

Abnormal 

Unusual 

Abnormal