I would "hazard a guess" that theoretically, at this time, there is no need for parts available to the customer given that these locomotives have a 2 year warranty.
Lionel probably prefers folks send these $2000 locos in for any repairs for the near future as opposed to opening them up possibly causing more harm.
At the same time they probably don't want people buying up extras of this or that, leaving them less parts for warranty repairs.
I'm not say that yourself or any other of the folks that are capable of tweaking repairing these shouldn't. I'm just looking at it from Lionels point of view.
There have been folks that have done mare harm than good.
At some point there will likely be a full list of parts up, just not this early in the warranty period.