The Mercedes-Benz GL-Class gearbox powers an imposing leisure SUV launched in 2006, updated in 2013, and later renamed the GLS. Voted SUV of the Year in the North American market, the GL-Class uses a single gearbox fitted as standard across the entire range: the 7G-Tronic, a seven-speed automatic gearbox with a well-earned reputation for reliability and robustness. Heavy use or a fault can, however, shorten its service life. EDEN BOITES explains how to prevent problems with your gearbox.
Gearbox oil changes to protect the GL's transmission
The essential role of gearbox oil
Gearbox oil performs three key functions on your GL-Class:
- It reduces friction between internal components through effective lubrication and preserves the integrity of the seals;
- It dissipates the heat generated during driving, preventing overheating;
- Its detergent properties clean the components by carrying away metallic particles.
Check the quality and level of oil in your GL periodically. The dipstick has two marks: if the level falls below them, your vehicle likely has a leak that needs to be identified and repaired. If the oil has turned black, it is saturated with residue and an oil change is overdue. As a general rule, this should be carried out every two years or every 60,000 kilometres, whichever comes first. To understand how this component works, read our article on how a gearbox works.
How to carry out a gearbox oil change
An oil change requires only a few basic tools:
- Park the vehicle on a flat surface and raise it;
- Locate the transmission oil sump beneath the vehicle;
- Place a drain pan underneath, then remove the drain plug;
- Allow the oil to drain fully, clean the sump, and replace the seals if necessary;
- Pour in the new oil specified by the manufacturer, using a funnel;
- Check that the level sits between the two marks on the dipstick;
- Start the engine and let it run for a few minutes to circulate the oil;
- Cycle through all gears, including reverse, then check for leaks.
If you would rather not do this yourself, your mechanic can take care of it quickly.
GL-Class gearbox fault symptoms and how to handle them
An oil change resolves certain issues, but other faults require the attention of a professional mechanic. Pay close attention to any noises, vibrations, juddering, or loss of performance from your GL-Class, and note these symptoms to help the professional make their diagnosis. Most problems can be sorted at the garage, but the more complex ones demand considerable time and resources.
In cases of advanced deterioration, your mechanic will recommend a complete gearbox replacement.
Exchange or second-hand gearbox for the GL?
Rather than buying a brand-new gearbox at full price, there are two alternatives. A second-hand unit is cost-effective but its history is unknown. An exchange gearbox is one that has been stripped down, cleaned component by component, with all faulty parts replaced and the whole unit rigorously tested: you get a product as good as new at a second-hand price. To choose the correct 7G-Tronic reference for your GL, have your registration number to hand.
Frequently asked questions
How often should I change the oil in the GL's gearbox?
As a general rule, every two years or every 60,000 kilometres, whichever comes first. Refer to your GL-Class owner's manual for the manufacturer's recommendation.
How do I know if my gearbox oil needs replacing?
If the oil on the dipstick has turned black, it is saturated with residue and must be replaced. A low level often indicates a leak that needs to be identified.
When should I consider a complete replacement?
When deterioration is advanced and repair at the garage is no longer cost-effective, an exchange gearbox becomes the most sensible solution for the GL.
Does an exchange gearbox come with a warranty?
Yes, our exchange gearboxes come with a warranty of up to 24 months and a satisfaction-or-money-back guarantee in accordance with our Terms and Conditions.
For further reading, see our advice on maintaining the G-Class and on the S-Class gearbox.
Why choose EDEN BOITES?
Browse our reconditioned Mercedes gearboxes, sold on an exchange basis. Every gearbox is stripped down, cleaned component by component, with all faulty parts replaced, then tested by our experts. You get a product as good as new at a second-hand price, backed by a warranty of up to 24 months. Payment can be spread over up to 10 instalments, and we deliver throughout France and the European Union, with lead times confirmed on request. Exchange gearboxes are offered with a satisfaction-or-money-back guarantee in accordance with our Terms and Conditions.
Have your registration number ready and contact us for personalised advice tailored to your GL-Class — it's quick and there's no obligation.
