Replacement planetary gear assembly for the Mercedes 4Matic transfer case behind the 722.9 7-speed, OE A2212708604 and A2212701843, fits GLK250/350.
This is the planetary gear set for the 4Matic transfer case bolted to the back of the 722.9 7G-Tronic, referenced to OE numbers A2212708604 and A2212701843. It is listed for the Mercedes-Benz GLK350 4Matic and the GLK250 BlueTEC 4Matic. Most people looking for it already have a GLK that growls from under the center of the car, binds in tight turns, or showed metal when the transfer case was opened, and they want the center differential section without paying dealer money for a complete case.
On the GLK, Mercedes did not hang a separate chain-drive transfer case off the transmission. The power transfer unit sits in a compact housing behind the 722.9 case, and the front axle shaft exits at an angle toward the front differential. Inside, the planetary set is the center differential. The drive gear has the sun gear teeth cut into it, the ring gear shaft connects to the transmission output, and the carrier feeds the rear output flange. Transmission Digest's teardown of a 2010 GLK350 describes the detail that makes this unit different: a set of clutch plates lives inside the planet carrier, inner plates splined to the sun gear and outer plates to the carrier. A plate spring keeps that pack preloaded, so the gearset turns as a unit in normal driving and only slips when one axle starts spinning faster than the other. The split between the axles is fixed; there is no transfer case module or actuator on this unit.
Noise is the most common 4Matic complaint and it is easy to blame the wrong part. Put the car on a lift and use a stethoscope to rule out the front and rear differentials and the propshaft center support bearing; disconnecting the rear driveshaft can take that bearing out of the picture. In the GLK teardown above, the growl turned out to be two pitted bearings in the transfer unit, not the gears, so inspect bearings and gears together once it is apart. If the noise really comes from inside the 7-speed, start with our 722.9 common problems guide, and check leak points with the 722.9 fluid leak guide.
Listed fitment is the X204 GLK350 4Matic and GLK250 BlueTEC 4Matic, which share the W204 C-Class platform and the 722.9 with this integrated transfer unit. Mercedes used several 722.9 variants and more than one 4Matic design, and later models with a power take-off on the rear propshaft use a different layout entirely. Compare A2212708604 or A2212701843 with the part in your case, or send us your year and VIN before ordering. Our 722.9 identification guide shows how to read the transmission tag, and the rest of the hard parts are on the 722.6/722.9 parts page.
| OE numbers | A2212708604, A2212701843 |
| Transmission | Mercedes 722.9 7G-Tronic with 4Matic transfer case |
| Vehicles | Mercedes-Benz GLK250, GLK350 (W204 platform) 4Matic |
| Weight | 7.45 lb |
Doing this repair right usually means replacing these at the same time. Same transmission, ships together.
It is listed for the GLK350 4Matic and the GLK250 BlueTEC 4Matic with the 722.9 and integrated transfer unit. Match A2212708604 or A2212701843 against your part, or send your year and VIN and we will check it.
No. It is the planetary gear set, the center differential section with its internal clutch pack. The housings, drive and driven gears, bearings and seals are not included.
Not always. In a documented 2010 GLK350 case the growl came from pitted bearings in the transfer unit. Rule out the differentials and propshaft support bearing first, then inspect bearings and gears together once the unit is open.
Replace the torque-to-yield Torx bolt that holds the planet set, any pitted bearings and races, and the seals. Clean the orifice plug in the cooler return line that feeds oil to the transfer unit.
The transfer unit runs on Mercedes-approved automatic transmission fluid, not gear oil. Refill the 722.9 with the ATF specified for your car and check the level hot as Mercedes specifies.
