Mercedes 4MATIC Transfer Case Bearing and Seal Rebuild Kit

This is the bearing and seal set for the Mercedes 4MATIC transfer case (the NP-series unit bolted to the back of the 722.6 and 722.9 automatics). It covers the reference numbers NP604623, NP925485, 0159971246, 0139977246, NP312842 and NP577617, so it drops into the common C, E, S, CL, CLS and GLK all-wheel-drive applications rather than one single chassis.

Fitment covers C230, C280, C300 and C350 4MATIC, CL550, CLS550 and CLS63 AMG from 2006 to 2014; E280, E300, E320, E350, E500, E550 and E63 AMG 4MATIC from 2004 to 2014; and GLK250, GLK350, S350, S450, S500 and S550 4MATIC from 2004 to 2015. Verify your existing case casting number before ordering if the vehicle has already had a transfer case swap.

These cases fail in a predictable way. The front output shaft seal starts weeping onto the subframe, the chain stretches, and the input and output bearings get noisy under load - usually a whine that changes with road speed rather than engine speed, plus a puddle of gear oil under the bell housing area. Once the bearings are loose the chain wanders and eats the case. Replacing the bearings and seals at the first sign of a leak is what keeps the housing usable.

On the bench: pull the transfer case off the transmission, split the housing, press the old bearings off the input and output shafts, and drive the new races in square with a seal and bearing driver set. Set the new front and rear output seals flush and lube the lips before the shafts go back through them. Refill with the correct Mercedes transfer case fluid on reassembly - these units take a specific spec fluid, not gear oil.