In this article the common faults of the gear box will be discussed and suitable remedies suggested.
1. Noisy Operation of the gear box :
There may be two different cases i.e, the noisy running when the vehicle is stationary or when it is running in various gears.
(A). Stationary running :This noise may be due to any or moreof the following reasons:
• The bearings may be worn out in which case they will have to replace.
• Countershaft may be worn, bent or having large end play. This has to be replaced with a new countershaft.
• Constant mesh gears may be worn out. The only alternative is their replacements.
• Shortage or incorrect grade of lubricants .This gear box should be filled with specified lubricants.
(B) . When Vehicle is moving : The possible causes of troubles in this situations are listed below:
• Gears may be worn out: they have to be replaced.
• Gears may be loose on the main shaft .This may be due to worn out splines or the gears on the main shaft. The worn out part should be replaced to remedythe defects.
• The bearings may be worn out in which case they should be replaced.
• The lubricant may not be sufficient or of wrong specification.If this is the reason of noisy running .the gearbox should be lubricated immediately with proper grade of lubricant, other wise running without lubrication will causewear of many parts of gear box.
• Mountings bolts may be loose which may be tightened.
2. Hard Gear Shifting: The following may be the possible causes :
• Clutch adjustment may not be correct, which should be corrected.
• Clutch linkage may be binding.The same may be required or lubricated as required.
• There may be misalignment of the clutch housing.The runout at rear of clutch housing may be checked and corrected if necessary.
• The gear shift mechanism may not adjusted or lubricated properly,which must be done immediately.
• Synchromesh unit may be jammed or damaged .The damaged parts should be replaced .if no damage is there , then lubricate the unit immediately.
• Gear lever ball joint may be binding ,which should be lubricated.
3. Gear clash while shifting: If the gear clash while shifting from one gear to another ,the probable causes are :
• Adjustment of clutch may be incorrect, which may be checked and corrected if necessary.
• Clutch linkage may be binding, which may be repaired or lubricated as required.
• Misalignment of the clutch housing may be another reason , which may be checked at rear face and corrected if required.
4. Gear locked in one gear : If the gear is locked in one position and cannot be shifted out of that gear, the causes probably are :
• Selector fork may be bent or selector rod may be worn or broken , centre detent plug may be loose or even missing . To correct, inspection the various components of the gear shift mechanism and replace the defective.
• Teeth on any gear may be broken .After inspection the defective gear has to be replaced.
• Any other parts of the gear train may be worn or broken, To remedy, gear box has to be disassembled and defective parts replaced.
5. Gear Slipping: It may be experienced sometimes that the gear once engaged jumps out of engagements. The possible causes of this troubles are :
• The selector mechanism may be worn out or the springs may be weak.The replacement is the only remedy in this case.
• Gear on the main shaft may be very loose in which case it has to be replaced.
• The gear teeth or the dog clutch members may be worn out, which should be replaced.
• The worn out bearings may also be source of this troubles by causing excessive end play of gear box shafts. The defective bearing must be replaced.
6. Leakage of the gear box oil : The possible reasons for this may be :
• Damaged oil seals, which should be replaced.
• Damaged or even missing gaskets. The only alternative is the replacements.
• The bolts on the gear box cover may be loose , which should be tightened properly.
• The oil used may be thinner than the one specified . In this case the entire oil has to be drained and replaced with a fresh oil of suitable specifications.