Skip to content

Transmission service and fluid change

For years many manufacturers listed automatic transmission fluid as a lifetime fill — meaning the life the manufacturer plans for, not the life the gearbox could reach. Transmission fluid ages under heat and shear, and the clutch packs wear; the debris stays in the fluid. A change at the right time costs far less than a rebuild.

What it covers

  • A fluid change to the manufacturer's approved specification — every gearbox type has its own
  • Sump, filter and gasket where they form one unit
  • Setting the level at the prescribed fluid temperature, not by quantity
  • Observing the separate, shorter interval on dual-clutch gearboxes

What tells you it is due

  • Shift shocks, especially in the lower gears and when the gearbox is cold
  • A delay between selecting a gear and drive engaging
  • The gearbox holding revs briefly before the next gear takes
  • Oil spots under the car around the bellhousing

Worth knowing

A common piece of advice is to leave a very high-mileage gearbox alone if the fluid has never been changed. That is not superstition: fresh fluid with different friction properties can cause slip in a worn gearbox. A workshop that raises this openly, rather than simply selling the service, knows what it is talking about.

Find a workshop

Other services