Abstract: Self-loading/unloading transport trailers include at least one rearwardly extending frame extension foot which is positioned below a rearward cross-brace of the cradle frame. During a loading/unloading operation, the rearwardly extending frame extension foot will engage the ground surface to cause the cradle member to pivot thereabout and physically lift the wheel assemblies out of ground-engagement. Continued pivotal movement of the cradle member about the ground-engaged frame extension foot will then allow the cross-brace to come into contact with the ground and will thereby cause the frame extension foot to become disengaged with, and the wheel assemblies to be further incrementally lifted above, the ground surface. A manually actuated mechanical brake assembly is provided in order to arrest rearward movement of the transport trailer during a loading/unloading operation and thereby allow the cradle frame to initially pivot about the journal axis of the wheel assemblies.