Car servicing

DSG and Automatic Gearbox Servicing Explained

Automatic transmissions are not all the same, and neither are their service requirements. Your handbook and the manufacturer schedule decide, not a generic interval.

Published by the Serviced247 editorial teamLast reviewed 29 August 2026Evergreen - reviewed annually

Automatic gearbox servicing generates a lot of confident, contradictory advice online, largely because people generalise from one transmission type to all of them. The useful starting point is knowing which type your car has and what its own schedule says.

Key takeaways

Dual-clutch (DSG/DCT), torque-converter and CVT gearboxes are different designs with different maintenance needs.
A "sealed for life" transmission is a manufacturer classification, not a promise about your ownership.
Fluid specification matters as much as the interval: the wrong fluid can cause its own problems.
Gearbox servicing is normally separate from a routine car service and priced separately.
New or changing symptoms should be diagnosed rather than treated with a fluid change and hope.

The three common types

Dual-clutch (DSG, DCT, PDK, Powershift) - two clutches and an automated manual gearset. Wet-clutch versions run in oil and commonly have a specified fluid and filter interval; dry-clutch versions differ.
Torque converter automatic - a hydraulic coupling with a planetary gearset. Many have a specified fluid service; some are classified as filled for life.
CVT - a belt or chain running between variable pulleys, using a fluid specific to that design and frequently sensitive to using the correct one.

Electric vehicles usually have a single-speed reduction gear rather than a multi-speed gearbox, with its own, generally simpler, requirements.

Why there is no universal interval

Manufacturers set transmission fluid intervals for a specific gearbox, fluid and application. Two cars from the same brand can have different requirements depending on the gearbox fitted. Towing, heavy urban use and performance driving can also bring intervals forward on schedules that include severe-use provisions.

Where a manufacturer describes a transmission as filled or sealed for life, that classification is made against a design life assumption. Owners keeping a car longer, or using it harder, sometimes choose a fluid service anyway. That is a judgement call to discuss with a specialist familiar with the gearbox - not something to have done reflexively.

What a gearbox service normally involves

Draining and refilling with the exact specified fluid, to the specified quantity and fill procedure
Replacing the filter and sump gasket where the design has them
Setting the fill level at a specified fluid temperature on many units
On some dual-clutch units, a basic setting or adaptation reset with manufacturer-level software

Fill procedures on many modern transmissions are temperature-dependent and cannot be done accurately by eye. Ask how the garage sets the level.

If the gearbox is already behaving oddly

Hesitation, jerky engagement, slipping, warning messages or a transmission going into a limited-function mode are symptoms, not diagnoses. They can stem from fluid condition, but also from mechatronic units, clutch wear, sensors, software or engine-side faults.

A fluid change on a transmission with an existing mechanical fault will not fix the fault. Have the fault diagnosed first, and ask for the fault codes and what they indicate.

If the car enters a limited-function or limp mode in traffic, drive to a safe place and stop rather than continuing a long journey. Arrange recovery if the car cannot be driven safely.

Questions to ask before booking

Which transmission is fitted to my exact model and engine?
What does the manufacturer schedule specify for it, by time and mileage?
Which fluid specification will you use, and how much?
Is the filter included, and is the sump pan replaced or reused?
How is the fill level set, and is any software procedure required afterwards?
What is included in the quoted price, and what could add to it?