Having a specific SA hub model would help. Does the hub also include a coaster brake, a light generator, a drum brake? Usually there's a model and date of manufacturing on the hub shell, between the flanges.
Have you tried to add oil to the hub? Is the oil hole still in the hub shell? SA AWs are pretty reliable with rarely a broken part. But they can be sensitive to rust and adjustment. Lastly have you removed the chain yet?
Perhaps the best first stop to understanding the SA AW hub is
Internal-Gear Hubs (sheldonbrown.com) Andy