Gearbox Problems and Defects: A Troubleshooting Guide

Geaaarbox problems defects, Noisy gear shifting

Which are the common gearbox problems & defects?

The gearbox is one of the most important components in a vehicle. The gears and cones wear out due to constant usage and friction and later develop hard or noisy gear shifting problems. Hence, its performance deteriorates. Here, we look at some of the common gearbox problems and defects in a vehicle.

While driving a car, you may come across some of the following symptoms. These are the results of the vehicle getting older, and it has covered a significant distance. However, there are numerous reasons for each symptom.

1. Hard and/or noisy gear shifting: Gearbox Problems

One of the symptoms is hard or noisy gear shifting. If so, then the following could be the reasons.

  • Check the synchro-cone wear – If worn out, then change synchro-cone and gear.
  • Insufficient lubricant, improper grade, or quality of gear oil. – Fill to the proper level with recommended oil and rectify Leakage, if any.
  • Defective clutch linkage or gear linkage. – Adjust clutch/gear shift linkages
  • Damaged main shaft spigot roller bearing. – Replace damaged parts.
  • Worn or wrapped gear shift fork/shifter rods etc. – Repair or replace the damaged parts.
  • Shifter sleeve tight on matching – Repair or replace as necessary.

A worn out synchronizer cone often causes noisy gear shifting in vehicles.

2. Slipping out of gear

  • The gear shifter rod is shallow at the front – Replace the shifter rod.
  • The pressure spring is weak or broken, which could be one of the gearbox problems. – Replace the pressure spring.
  • Dog teeth on gears worn out. – Replace the affected gears.
  • The shifter sleeve is worn out. – Replace the affected sleeve
  • Shifter fork thrust pad/surface worn out. – Replace the damaged parts.
  • Excess end-play in the drive, main counter – Replace/repair as needed.
  • Gearbox mounting became loose. – Tighten the mounting.

3. Sticky Gears: Gearbox Problems

  • Insufficient lubricant, improper grade, or quality. – Fill with recommended oil, rectify the leakage, if any.
  • Sliding shifter sleeve synchro-cone jammed – Repair/replace as needed.

4. Noisy gear operation

  • Insufficient lubricant, improper grade, or quality could be one of the gearbox problems – Rectify leakage, if any & fill to the proper level with the recommended oil.
  • Excess end play in drive, main, or countershaft. – Repair / replace defective parts
  • Gearbox out of line with clutch housing. – Loosen gearbox mounting and realign and secure it correctly.

5. Loss of drive

  • Defective clutch – Rectify/replace the clutch.
  • Worn teeth on affected meshing gears could be one of the gearbox problems – Replace the damaged parts.

6. Repeated gear failure: Frequent gearbox problems

  • Chocked breather – Clean / Rectify / replace breather
  • Insufficient or improper grade or quality of gear oil – Fill to the proper level with recommended oil after stopping leakages
  • Defective clutch – Adjust or replace the clutch.
  • Improper assembly or installation of the gearbox could be one of the gearbox problems, or it could be the incorrect location of the shifter sleeve on the main shaft during assembly. – Gearbox front face must fit flat flush with the mating clutch housing face. Tighten bolts only after the gearbox is in its place.

In conclusion, carrying out periodic maintenance is the most crucial factor in getting your vehicle’s best performance. Always use the correct grade of oil at a proper frequency as recommended by the vehicle manufacturer. This habit of adequate maintenance would reduce the downtime for your vehicle.

Read more: Clutch problem and defects: What are the top reasons?>>

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