- 05/30/2025
- 2min
Changing the Transmission Oil in Automatic and Dual-Clutch Transmissions

A professional transmission oil change in modern automatic and dual-clutch transmissions requires high expertise, the right equipment, and a systematic approach. Optimal function and longevity of the transmission can only be ensured if all steps are carried out carefully. To ensure an efficient and professional oil change, we recommend observing the following steps:
1. Check the Service History
Before starting the oil change, the vehicle's service history should be reviewed. It is important to check when the last transmission oil change was performed and whether the change intervals specified by the manufacturer were observed.
2. Test Drive the vehicle together with the Customer
Performing a test drive before starting work, ideally alongside with the vehicle owner, is recommended. This is the only way to identify and document any abnormalities in shifting behavior or transmission function in advance.
3. Additional diagnostic steps in cases of unclear service history or abnormalities
If there is no complete service history or the vehicle has a high mileage or noticeable transmission problems, additional diagnostic steps should be performed:
- Reading the error log to check for OBD II codes.
- If codes are present, additional diagnosis may be needed.
- Taking a used oil sample to assess fluid condition
4. Performing the oil change according to the manufacturer's specifications
The actual oil change must always be carried out according to the vehicle manufacturer's specifications. We recommend using appropriate flush equipment such as the LIQUI MOLY Gear Tronic.
A professional process includes the following steps:
- Cleaning the transmission system with our Pro-Line Automatic Transmission Cleaner
- Draining and flushing the entire oil circuit
- Changing the transmission oil filter
- Filling with fresh transmission oil. Use the LIQUI MOLY oil guide to find the correct transmission fluid.
- Checking the fill level with a suitable diagnostic tool at the specified oil temperature.
- Final test drive.
Contact Liqui Moly's technical support to answer any questions.
Phone: +49 731 1420-871 (international)
Email: support@liqui-moly.de