I was just given this self drive Victa, I know what Norm is talking about these mowers being hard to push when the engine is not running but this mower pushes in both directions easily when not running and if I activate the self drive lever the mower will still push forward easily but not backwards.(one way clutch in side gears working)
I was looking at the gearbox and noticed the return spring so was thinking if they don't freewheel easily the gearbox is not disengaging completely.(too much drag )
This one looks like it all works because when the lever is engaged and the zip cord is pulled the mower drives in the forward direction.