Automatic gearboxes – preventative maintenance

Posted on April 26th, 2018 by Rob Marshall

Automatic gearboxes - preventative maintenance

While modern automatic gearboxes have evolved considerably since the 1980s, they still require to be looked after. Following this general advice will help your automatic transmission last for as long as possible.

Getting your definitions right

The advice given applies to the ‘traditional’ format automatic gearbox, with an epicyclic drivetrain and torque converter clutch. It does not refer to automated manual transmissions, including single, or twin-clutch types.

 Preventative maintenance

Modern automatics depend on the correct fluid quantity and specification for optimum reliability. Follow any level check advice carefully, because it is easy to get things wrong. Take extra care to ensure that you pour new fluid through the correct aperture and do not dismantle part of the gearbox unintentionally, by undoing an external bolt instead of a plug.

The oil should be clean. Dark coloured fluid indicates a major internal problem, caused possibly by overheating, or deterioration of the internal clutch friction plates. While many transmissions are quoted by car manufacturers as being ‘sealed for life’, it is realised that periodic fluid changes are beneficial on an older vehicle.

Pay attention on a road test, too. Any jerks, clunks, harsh changes, or a sudden engine speed rise between gear changes (‘flaring’) all need investigation. It is possible that such conditions might not illuminate a warning lamp on the instrument panel.

Our next blog will investigate how you can pre-empt an automatic gearbox’s condition, without even getting your hands dirty.