Gearbox Fault Diagnosis

Gearbox fault diagnosis

Below are a few common symptoms of transmission fatigue, excessive wear or impending failure. As with most things the quicker a problem is identified and remedied the less damage is caused in the long run, and less components will be affected.

Usually, the first sign of mechanical problems in your gearbox is sound. This can usually be divided into 5 distinctive categories:

• Crunching; this is the most common complaint with gearbox faults and can usually be felt as well as heard when changing gear. This is most commonly caused by excessive wear in the synchronizer blocking rings. This can be a result of speed shifting, poor lubrication or the clutch not fully disengaging. This can result in the transmission jumping out of gear and eventually complete failure.

• Whining and howling; this is usually a sign of a previous or current lubrication issue, either the quality or lack of. If the gear teeth mesh with insufficient oil film on the faces that contact, the metal will deteriorate and create a noise. Changing the oil may reduce the noise and smooth the meshing but if the gear faces are damaged unfortunately, they will never repair themselves and are likely to deteriorate further.

• Rumbling and growling; this is usually symptomatic of bearing wear or failure within the gearbox, usually caused by tiny fragments of swarf or dirt causing the bearing to operate less efficiently and eventually fail with far worse implications. It should be noted that the bearings not only aid smooth movement of rotational parts, it retains correct clearance levels between gears which can be adversely affected with bearing wear.

• Buzzing and hissing; this is usually experienced while the vehicle is accelerating or slowing and is usually caused by a loose bolt or rubber isolator and may be relatively simple repair before serious damage is caused to internal components.

• Banging and clunking; often be experienced when the motor mount becomes loose or damaged. Another frequent sign of a damaged motor mount is clutch chatter.

If you have specific concerns relating to the smooth running of your gearbox, call one of our technicians today so we can advise you of the best course of action.