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Home >> Volvo >> 2008 >> V70 >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Differential Electronic Module (DEM), Driver Information Module (Dim), Engine And Engine Control Module (ECM) - Design And Function >> Differential Electronic Module (DEM) (2009-2010) >> Function >> Mechanical Function, Overview
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Mechanical Function, Overview

Fig 1: Cutaway View
GLL168857Courtesy of VOLVO CARS CORPORATION
  1. Output shaft.
  2. Input shaft
  3. Inner and outer wet clutch plates
  4. Operating piston

The transmission and bevel gear transfers engine torque to the propeller shaft. The input shaft is joined to the clutch's output shaft via the multi-plate clutch pack. The multi-plate clutch in the coupling must be engaged to transfer torque to the rear axle. The inner and outer wet multi-plate clutch are the transfer point between the input and output shafts.

The feed pump builds up an oil pressure which then Differential electronic module (DEM) controls via the pressure reducing valve, so that correct pressure is obtained. Then the working piston is applied against the disc pack so that the clearance is eliminated and the clutch is prepared to enable quick reaction and control. At 27.5 bar deployed pressure from the pressure reducing valve max. torque is reached, 1, 500 Nm, through the clutch to the rear wheels already at start.