Automatic Gears



Automatic Gear Box Faults  

(1) Gear shift lever stuck or hard to move.   
(2) No drive while in D position.
(3) Gears engage roughly.
(4) Gears engage slowly.  
(5) Gears do not change automatically while in D position. 
(6) Transmission slips while in D position.
(7) Gears do not shift beyond the second gear, while in D position. 
(8) Gears shift from first gear to third gear while in D position. 
(9) Abnormal gear box noise. 
(10) Transmission oil leaking. 




(1) Gear shift lever stuck or hard to move.
Possible Causes :
1. Manual shift valve improperly positioned.
2. Mechanical valves inoperative. 
3. Valve body external cover improperly installed.

(2) No drive while in D position.
Possible  Causes :
1. Low transmission oil pressure due to,
       (A) Low oil level
       (B) Defective oil pump or loose oil   tubes
       (C) Oil line or screen plugged
2. Incorrect manual valve linkage adjustment
3. Defective clutch or band
4. Defective over running clutch

(3) Gears engage roughly.
Possible  Causes :
1. Engine idle speed too high.
2. Vacuum diaphragm leaking.
3. Manifold vacuum line obstructed.
4. Throttle valve control cable improperly adjusted.
5. Sticking regulator booster valve.

(4) Gears engage slowly.
Possible Causes :
1. Engine idle speed too low.
2. Manual shift valve improperly positioned.
3. Delayed hydraulic pressure build up.
4. Hydraulic valves defective.

(5) Gears do not change automatically while in D position.
Possible  Causes :
1. Throttle valve cable improperly adjusted.
2. Vacuum modulator defective.
3. Governor not working properly.
4. 1-2 or 2-3 shift valves sticking.
5. Band or clutch defective.
6. Low transmission oil pressure due to,
    (A) Low oil level.
    (B) Defective oil pump.
    (C) Oil line or screen plugged.

(6) Transmission slips while in D position.
Possible  Causes :
1. Low transmission oil pressure due to,
    (A) Low oil level.
    (B) Defective oil pump or loose oil tubes.
    (C) Oil line or screen plugged.
2. Incorrect gear shift linkage adjustment.
3. Defective clutch or band.
4. Vacuum modulator defective.

(7) Gears do not shift beyond the second gear, while in D position.   
Possible Causes :
1. Throttle valve cable adjustment incorrect.
2. Throttle valve defective.
3. Control pressure incorrect.
4. Governor defective.

(8) Gears shift from first gear to third gear while in D position.
Possible Causes :
1. Control pressure incorrect.
2. Intermediate band adjustment incorrect.
3. Intermediate servo unit defective.
4. 1-2 shift valve defective.

(9) Abnormal gear box noise.
Possible  Causes :
1. Noise in R and D positions :
    (A) Torque converter defective                        
2. Noise in 1, 2, 3 or D positions :
     (A) Forward clutch locked 

(10) Transmission oil leaking.
Possible  Causes :
1. Gear box oil seals damaged or improperly installed.
2. Valve body bolts not tightened properly. 
3. Oil cooler tubes damaged or connections defective or loose.
4. Oil drain plug defective or loosely fitted.