Torque Shop: Signs of gearbox issues

Jerky gear shifts, commonly referred to as "shift-shock", is one of the signs of gearbox problems.
Jerky gear shifts, commonly referred to as "shift-shock", is one of the signs of gearbox problems.PHOTO: ST FILE

How will I know if my car's gearbox is going to have problems? Are there early signs to look out for?

With a manual gearbox, which is rare these days, repairs or even overhauls are relatively inexpensive. For example, the clutch set, a regular wear-and-tear item, costs between $200 and $800.

Fixing an automatic transmission is a far costlier affair because repairs often involve many sophisticated components.

The first sign of a failing automatic gearbox is delayed shift when selecting Drive mode from Park. This behaviour is quickly followed by tardy response to the accelerator pedal.

Engine revs rise, but the car moves at a leisurely pace. These symptoms might disappear when the engine and transmission are warmed up, but they should not be ignored.

Jerky gear shifts, commonly referred to as "shift-shock", is another sign of gearbox problems. This can be during gentle acceleration or in the case of continuously variable transmission, when selecting Drive or Reverse from Neutral. In some instances, the transmission might refuse to shift up.

Vibrations in the drivetrain from a high-mileage vehicle are rare, but any such signs should also be checked. Sometimes, broken gearbox mountings cause vibrations that may eventually affect internal components.

In general, any unusual transmission behaviour should be checked immediately regardless of the car's mileage. Overhauling an automatic transmission can cost more than $3,000, while a replacement unit can easily exceed $10,000.