193 

 

No. 144 Trip stop of fourth gear of transmission case   

Malfunction Causes 

Solution 

Shifting operation mechanism incorrectly adjusted

Adjust shifting operation mechanism (gear shifting lever o
shift tie-line); 

Synchronizer of third, fourth gear loosens   

Check adapting of synchronizer ring and drum of third, 
fourth gear loosens, and replace it if abnormal; check 
slide block of synchronizer of third, fourth gear is 
excessively worn, and replace it if abnormal; 

Shift fork shaft of third, fourth gear self-locked, 
interlocking mechanism poor   

Check self-locked groove of shift fork shaft of 
synchronizer of third, fourth gear and transmission 
housing are incorrectly positioned; check shift fork shaft if 
abnormal; check grooving position of self-locked groove is 
correct; replace shift fork shaft if abnormal; check position 
of transmission housing hole is up to standard; replace 
transmission housing if abnormal;   

Shift fork of third, fourth gear excessively worn 
(4-gear end face)   

Check shift fork shaft is deformed or worn; replace it if 
abnormal; 

Auto trip stop of 
fourth gear of 
transmission 
case 

Fourth-gear of output, input shaft worn, appearing 
severe taper   

Replace fourth-gear of output, input shaft; 

 

No reversing gear 

Shifting operation mechanism 

incorrectly adjusted 

Reversing locking mechanism 

worn, damaged 

Reverse gear malfunction 

Replace 

Adjust 

Replace 

Normal 

Abnormal 

Normal 

Abnorma 

Abnormal 

 
 

 

 

194 

 

Trip stop of fourth gear of transmission 

case 

Shifting operation mechanism incorrectly 

adjusted 

Synchronizer of third, fourth gear loosens 

Shift fork shaft of third, fourth gear self-locked, interlocking 

mechanism poor 

Shift fork of third, fourth gear excessively 

worn 

Fourth-gear of output, input shaft worn, 

appearing severe taper 

Repaiar or replace 

Replace 

Adjust 

Replace 

Repair 

Normal 

Abnormal 

Abnormal 

Abnormal 

Unusual 

Abnormal 

Normal 

Normal 

Normal 

 
 

 

 

195 

 

No. 145 Transmission with abnormal sound   

Malfunction Causes 

Solution 

Poor transmission oil quality, quantity 

Check viscosity of transmission oil is too small, and quantity is too 
little. Fill in API    GL-4 SAE and oil level is flush with lower plane 
of oil filler;   

Bearing within transmission worn   

If any gear is sounding and park gear not sounding during driving, 
check each bearing within transmission is worn or loosening, and 
bearing shall move stably without abnormal sound. Shaking with 
hands shall be without loosening sound;   

Gear worn   

Meshing clearance of each gear pair within transmission is too 
large or too small, which shall be within 0.1-0.35mm. Measure it 
with several points, with measuring error at different positions not 
exceeding 0.15mm; 

Input shaft or bearing malfunction 

If any gear is sounding, and clutch disappears, check bearing is 
damaged; replace it if abnormal; check input shaft and output 
shaft is bent and measured with dial indicator, and with upper and 
lower runout no more than    0.1mm;   

Gear moving interfere 

Check chamfer of reversing cock wheel and driving and driven 
gear of the second gear is too small, making reverse gear scratch 
driving and driven gear of the second gear, and grind chamfer to 
make it larger; push reverse gear to the highest position with 
hands, making it not scratch driving and driven gear of the second 
gear; 

Transmission with 
abnormal sound 

Differential malfunction   

If any gear is sounding during driving, and park gear not 
sounding, check differential bearing or planet gear mechanism is 
damaged or clearance incorrect; if damaged, adjust or replace 
parts concerned; check bearing is damaged, and replace it if so; 

 

 
 

 

 

196 

 

Transmission with abnormal 

sound 

Transmission oil quality, quantity 

poor 

Bearing within transmission worn 

Gear worn 

Input shaft or bearing 

Gear moving interfere 

Replace 

Repair 

Replace or add 

Replace 

Replace 

Differential 

Adjust or replace 

Normal 

Abnormal 

Abnormal 

Abnormal 

Abnormal 

 Abnormal 

Abnormal 

Normal 

Normal 

Normal 

Normal