Torque Shop: Signs of impending gearbox failure

I drive a 15-year-old car. Lately, I have noticed that the automatic transmission takes longer to shift up to final drive. And occasionally, the gearbox seems slow to engage when I shift to D. Are these early signs of gearbox failure?

A car’s automatic transmission is a sophisticated piece of equipment. Components include a torque converter – operating in a fluid-filled encasement – with a series of hydraulically actuated clutches and brakes.

In any hydraulic system, the quality of the oil is critical for efficient, swift and reliable operation.

In this case, the automatic transmission fluid (ATF) provides the pressurised medium for actuating the various internal elements. Over time, the ATF deteriorates and loses its viscosity. This, in turn, results in wear and tear.

Replacing the ATF regularly will definitely prolong a transmission’s life. However, normal wear of friction elements and, sometimes, a defective valve, will cause a noticeable drop in the transmission’s functionality. Typical symptoms are slow gear changes, delayed shifting from N to D or R and, in extreme situations, reluctance to upshift or downshift.

At this stage, the only course of action is to either replace the transmission with a rebuilt unit from a reputable source or have your own unit overhauled by a transmission specialist. Unfortunately, there are very few specialists here who can do this.