(Oil Supply For 4MATIC Transfer Case Function - GF28.55-P-3010AVF)

MODEL 205 with TRANSMISSION 722.961/965 

Oil feed 

Courtesy of MERCEDES-BENZ USA

Oil return line from oil cooler 

Courtesy of MERCEDES-BENZ USA

Oil change in driving mode 

Courtesy of MERCEDES-BENZ USA

Function requirements for 4MATIC transfer case oil supply, general 

• Internal combustion engine running
• Drive train operational

Oil supply for 4MATIC transfer case, general 

The oil supply system ensures that the transfer case components are supplied with sufficient oil. The integrated design means that the distributor and automatic transmission have a common oil system.

Function sequence for 4MATIC transfer case oil supply 

A separate oil return line on the automatic transmission housing enables oil to flow from the oil return of the oil cooler to the transfer case. The oil feed is here limited to approx. 100 ml/min by means of a restrictor in the oil return line connector. An oil sump is formed in the final drive chamber and its oil level is regulated to a constant max. 700 ml. If the oil level on a vehicle at standstill rises to more than 700 ml, the oil flows off through the central tapered roller bearing in the automatic transmission. When in automotive operation the oil is hurled out of the final drive chamber, through the rotation of the helically geared spur gears, and up into the transfer case's pressure governing chamber. The oil is accumulated here and routed over the hole on the floor of the pressure chamber and back into the side output chamber. This principle ensures that the oil sump is kept as small as possible when in automotive operation, to prevent any high swirling of the oil. If the oil level in the pressure governing chamber rises above the max. level of 700 ml, the oil flows through an oil return hole into the automatic transmission. The oil supply for the planetary gear differential is provided through two holes between the final drive chamber and the planetary gear set chamber.