the soft handle screw drivers with the removeable shank has a different drive gear that has an indent for the spring ball to locate in on the shank. i believe they no longer supply repair kits for the soft handle type
SO doesn't supply Soft Grip ratcheting screwdriver repair kits because they don't exist and never did.
There are a few "experts" here on GJ that claim the kits exist but have never been able to provide a part number for these elusive kits.
I suspect this is because if you could get these elusive kits folks would never purchase Soft Grip ratcheting screwdrivers, instead they would purchase Hard Handle ratcheting screwdrivers and replace the internals with the kit.
SO sometimes does some strange things but they are NOT stupid.

They won't do anything to jeopardize sales of the Soft Grip.
Again I challenge anyone to find the P/N of this elusive Soft Grip ratcheting screwdriver repair kit. If it existed I would order a boat load and convert all my Hard Handle ratcheting screwdrivers to use removeable shanks.
The thing that really irk's me is SO wants folks to upgrade to the Soft Grip's but try and get some of the phillip's or Torx shanks... they are almost always back ordered or unavailable.