722.6 Planetary 2000-2006

This used OEM assembly pairs a 722.6 planetary gear set with its clutch drum and shaft, listed under Mercedes part number 140272112A and taken from a 2006 transmission. It is offered for 2000-2006 722.6 five-speeds, which covers the W203 C-Class, W211 E-Class and W163 ML era cars. When a rebuild uncovers a damaged gear set and a drum that is scored or cracked, buying the two already assembled saves sourcing them separately, and the piece in the photos shows the drum, gear set and shaft together.

Where this assembly sits in the 722.6

Inside the 722.6, three planetary sets are stacked between the input and output. The clutch drums wrap around them, and when a clutch pack in a drum applies, it locks one member of a planetary set to another, giving a new ratio. That arrangement is also why drum and gear damage tend to show up together: the drum bearings and the shaft bushings deliver lube oil to the pinions. Sonnax sells a bearing and seal kit for the K2 drum and a replacement input shaft bushing for this transmission specifically to stop planetary failure, and a bronze pinion washer with redesigned lube notches for the output shaft/center planetary.

Symptoms that lead here

• Noise that follows road speed and gets louder in one or two gears.
• Loss of a gear or no movement in some selector positions, with no electrical codes stored.
• Steel and bronze debris in the pan, the bronze often coming from worn washers and bushings.
• On teardown, a drum with heat-checked or worn splines and pinions with excess end play.

Check before ordering

The most common 722.6 complaints, flare between gears, harsh downshifts and limp mode, trace back to the valve body, solenoids or conductor plate rather than the gear train. Our 722.6 ML common problems guide and the 722.6 common problems and fixes page explain how to separate those faults from a hard-parts failure. Scan for codes, inspect the fluid and pan, and only commit to the gear train once you have mechanical evidence.

Fitment

Listed for 2000-2006 722.6 transmissions and pulled from a 2006 unit with part number 140272112A. The 722.6 was built in many variants with different gear and drum combinations, so match the number cast or stamped on your old parts, or compare the drum's spline count and the shaft against the photos. If that is not possible, send your year, model and VIN before ordering. Other internals are in our 722.6 and 722.9 parts collection.

Install notes

• Disassemble, clean and inspect: check drum bushing wear, seal ring grooves and pinion end play on this used part.
• Install new clutch packs, seal rings, thrust washers and bearings, plus a new input shaft bushing.
• Check the freewheel (sprag) units while the gear train is apart, since debris often reaches them.
• Flush the cooler, then fill with MB 236.14 approved ATF and set the level hot per the factory procedure.

For a full refresh, combine this assembly with the 722.6 overhaul kit, and if a freewheel shows wear, the 722.6 sprag clutch is the part to fit alongside it.

Is this just a planetary or a full drum assembly?

It is a used OEM assembly with the planetary gear set, its clutch drum and the shaft, as shown in the photos, listed under part number 140272112A.

Which cars does a 2000-2006 722.6 come from?

That span includes the W203 C-Class, W211 E-Class and ML models of the period, among others. Because variants differ, match your part number or send us your VIN.

Do the clutch plates need replacing?

Yes. Treat the clutch packs and seals as wear items and replace them with an overhaul kit; only the hard parts are reused.

What caused my original gear set to fail?

Usually poor lubrication. Sonnax addresses K2 drum bearing and input shaft bushing wear in this unit because they lead to planetary failure.

Which fluid and how much?

MB 236.14 approved ATF. Capacity varies by variant, so fill per the factory level-check procedure with the fluid hot and the car level.

• 722.6 Common Problems and Fixes
• 722.6 Mercedes ML Common Problems and Fixes
• 722.6 Mercedes ML Shift Problems: Diagnosis and Fix
• 722.6 Mercedes C Class Shift Problems: Diagnosis and Fix