Design And Function: Differential

WARNING: This page does not describe the selected car, but rather 9 other vehicles, including the 2009 Volvo S60, 2008 Volvo S60, 2007 Volvo S60, 2006 Volvo S60, and 2005 Volvo S60. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: Identifying Differential

Courtesy of VOLVO CARS OF NORTH AMERICA.

The differential consists of the differential housing, large and small differential gears, shaft journals and thrust washers. The differential housing is completely sealed so that if a drive shaft is removed no dirt can penetrate and no oil can run out.

The differential distributes power equally between the drive wheels, even if they are rotating at different speeds. When driving straight ahead, the ring gear and differential housing rotate at the same speed as the drive shafts and the driving wheels. When cornering, the differential gears rotate to compensate for the different speeds of the wheels. Because the small differential gears are rotating on the shaft journal, the drive shafts can rotate at different speeds. Power is transferred from the differential housing to the drive shafts via the small differential gears in the same way as when driving straight ahead. Both drive wheels still have the same driven power.

AWD

Cars with four wheel drive have a splined pin on the differential housing. The sleeve on the pin connects the differential housing with the bevel gear. This transfers the power to the rear wheels.