Mercedes 7G / 9G Gearbox Service & Repair in London

Mercedes Gearbox Service & Repair (7G-Tronic, 9G-Tronic)

We service and repair Mercedes 7G-Tronic (722.9) and 9G-Tronic (725.0) automatic gearboxes in West London — including the essential 40,000-mile oil and filter service, conductor plate replacement and torque-converter diagnosis.

Price: From £289 for a full 7G-Tronic service with genuine filter. Typical time: 3–5 hours

Mercedes calls its automatic gearbox "fill for life". In practice, we see far too many 7G-Tronic boxes fail at 120,000 miles because the oil was never changed. Change the fluid and filter every 40,000 miles and these are exceptionally reliable gearboxes. Ignore it and they are not.

Gearbox oil and filter service

We drain the gearbox, replace the internal oil filter, refit the sump with a new gasket, and refill with the correct Mercedes ATF — either MB 236.14 for 7G-Tronic or MB 236.17 for 9G-Tronic. Wrong ATF is the second-most-common cause of early failure.

Conductor plate (7G-Tronic)

A failing 13-pin conductor plate is one of the best-known 7G-Tronic faults: delayed engagement, limp mode, intermittent no-drive. Replacement is a day job with full adaptation reset on Xentry.

When it needs a rebuild

If the fault is mechanical — clutch pack wear, torque-converter failure — we work with a specialist rebuild partner and fit the unit ourselves.

What's included

ATF drain and refill (correct MB spec)
Internal filter replacement
Sump gasket replacement
Xentry adaptation reset
Conductor plate replacement on demand
Torque-converter diagnosis

Common symptoms we see

Jerky 1–2 upshifts
Delayed engagement from Park or Reverse
Limp mode ("F" on dash)
Judder at light throttle
Red "Visit workshop" gearbox message

Frequently asked questions

Does my Mercedes gearbox really need an oil service?

Yes. Despite "fill for life" marketing, every 7G-Tronic and 9G-Tronic box we see benefits from a fluid and filter service at 40,000 miles. It is the single best thing you can do for long-term gearbox health.

What are the symptoms of a failing Mercedes conductor plate?

Delayed engagement from P or R, limp mode ("F" on the dash), flaring between gears, or the car refusing to select gear when hot. All classic 7G-Tronic conductor plate faults.

My Mercedes automatic is slipping — can it be saved?

Sometimes. If it is fluid-related or a conductor plate issue, absolutely. If the clutch packs are mechanically worn, it usually needs a rebuild. A proper gearbox diagnostic will tell us which.