Transfer case oil supply, basic function

Overview

This document contains information on:

 General

 Function requirements

 Function

General

The oil supply system ensures that the components of the transfer case are sufficiently greased and cooled. There are the following types of oil supply to decide from:

 Oil supply through chain

 Oil supply through passive lubrication

 Oil supply through additional oil pump

Function requirements

 Engine in operation

Function
Oil supply through chain
The rotor-type oil pump (3) supplies the following rotating components with oil via transverse bores in the primary shaft (1):

 Center differential module

 Clutch pack

 Planetary gear set

 Primary shaft bearing (2)The rotor-type oil pump (3) is located in the front transmission housing of the transfer case and can generate high oil pressures at a high rate of flow. The output shaft bearing (6), front axle output flange sprocket (5) and chain (4) are supplied with sufficient oil by running through the oil sump. Metal abrasion and shavings are collected by a magnet (7) integrated into the rear transmission housing (8).
Passive lubrication (Transfer case with torque on demand function)
Lubrication happens passively. The oil picked up by the chain is conveyed by the centrifugal force at the upper deflections of the chain into a fluid reservoir from which point it is distributed to all further components of the transfer case.
Oil supply through additional oil pump (Transfer case with torque on demand function and low-range planetary gear set)
For oil supply through an additional oil pump, oil is supplied and lubrication occurs through an additional oil pump. In the transmission housing, integrated fluid reservoirs and oil guiding channels supply lubrication and cooling for important points of the transmission.

P28.55-2003-76