The solid ("live") rear axle has gotten a lot of bad press in recent years. Though technophiles insist that more modern independent suspensions are superior in every way, the fact remains that the traditional live axle does have its virtues.
The traditional live axle uses a ring and pinion gear to send power from an incoming drive shaft to the two drive wheels.
Live axles have traditionally used leaf spring suspensions, which can bear heavy loads more safely than an independent rear's coil spring suspension.
Because they form a solid link between the two tires, solid axles provide a constant amount of ground clearance. This can be a huge advantage off-road.
When compared to independent suspensions, live axles are usually stronger in both their ability to resist impact breakage, and the twisting associated with high-torque engines.
Solid axles are often used in drag racing because the center differential places a great deal of traction-enhancing "dead weight" directly onto the tires.
