Thanks Pete - I have tried and failed, causing an early life of the motor... I have plenty spares but with the wrong worm diameter on them ... thus my previous post of a nightmare of finding these parts. I have had no success of removing a worm and pressing one on with a new motor either... just don't possess the tooling to do that.
The can and flywheel gap have the board placed in between them. So I cannot envision how I could package a shim here. The more logical place maybe between the worm and housing at the lower end... at the base of the worm to the actual truck frame.