It was easier than I thought. Thanks to Mosslake’s generous instructions and photos on the AMR Forum, I got up the guts to dismantle the little guy and quiet him down. I labeled every screw I removed and the operation actually went very easy. I had more difficulty putting the tiny pipes back in their holes than taking the boiler off. With the motor exposed, I oiled the bearings with LaBelle light oil and added a little grease to the gears. The Shay runs a lot quieter now.
For those yet to undertake this project, be sure to unfasten the plastic pipe ends from the chassis (the ones attached to the vertical gear assembly) before the assembly comes off with the ashpan. Also, the two wire pipes on the boiler sides toward the front have to be guided back in their tiny holes before the boiler will seat.
Here is Mosslake’s helpful article:
http://www.all-model-railroading.co.uk/forum/showthread.php?t=1007