I have the same problem.you will find that the gear inside the planet hub has collapsed or teeth have stripped.metal gears are available from J.Lydon .Lydonsvacs@hotmail.com You will need to check that the flat on the planet hub drive shaft hole is not badly worn or damaged,if it is then we are both looking for a supplier of a PLANET HUB ASSEMBLEY,mod.A701A
Gerald
November 2008