The kind of independent suspension used on the rear of a vehicle depends in part on whether it is front-wheel-drive, or rear-wheel-drive.
If it is front-wheel-drive, it may use a McPherson strut system at the rear, similar to the front suspension system. There is normally no steering on the rear wheels, so there is no need for the bearing in the upper mounting.
On rear-wheel-drive vehicles, the suspension arrangement has to allow for the external drive shafts to transfer the drive to the wheels.
The final drive assembly is normally fixed to a cross-member, and since it must absorb the torque reaction, it must be secure. Drive shafts, either with conventional or constant velocity joints, transmit the drive to the wheels.
When conventional universal joints are used, each drive shaft may have a splined-section to accommodate changes in shaft length, due to changes in wheel camber, with suspension action. However, the drive shaft itself can be used as the upper link of the suspension, providing the pivot point. The splined-section is unnecessary, and the shaft can be made as a one-piece.
As with the front suspension, the lower link has widely-spaced pivots to provide stability, and the unequal-length links maintain the track nearly constant, although, with deflection, some camber change does occur.
In some designs, the wheel units are located at the outer ends of semi-trailing arms. The arms are attached to their cross-member pivot-points by rubber bushes, and constant-velocity joints are used at each end of the external drive shafts.
