vinkodex.5G-Tronic (722.6): control unit in oil, coolant in the ATF
Typically between 120,000 and 250,000 km. It does not show up on every car.
expensive
severity
between 120,000 and 250,000 km
mileage
1
sources
1 source next to the write-up.
The fault
How you spot it
The Mercedes 5 speed 722.6 automatic (5G-Tronic / NAG1) has three faults that also recur on the used market: (1) the control electronics sit inside the gearbox housing, and a leaking connector lets oil onto the electronics; (2) cooling faults around 2003 (and later) can let antifreeze into the ATF, which shortens its life; (3) wear of the torque converter lock-up clutch contaminates the valve body and causes jerky shifts.
The early cars (1995 to 2001) had planetary gear and freewheel wear; after 1998 to 2001 the design improved, and on the used market the W203/W211/W220 era is the typical find.
Which model
Who it affects
The card opens the generation, the engine or the transmission.
Engines and transmissions
Transmission
MB7226
vinkodex.Checklist
5G-Tronic (722.6): control unit in oil, coolant in the ATF
What you would check for this fault. Take it to the car.
Before you buy
Checklist
What you tick stays on this device only.
Sources
How we know
Information, not an expert opinion
We write the descriptions, and we put the source next to them. A person reviews them before they go out. They are still information, not a technical expert opinion.
- A fault on the list does not mean the car you are looking at has it.
- A fault missing from the list does not mean the model is fault-free. Write-ups are made model by model. Not all of them are done.
- You decide whether to buy. This is no substitute for an inspection. That needs a workshop and a history check.