So, several of us had issues with the nontraction wheelsets having too large a flange which caused a jump and increased noise when traveling over code 55 track. Well, yesterday, Athearn said that they would change out the wheel sets from four wheel sets on the loco (two on the lead truck, two on the trailing truck) and all seven wheel sets on the tender. Which is great that they will change them out without charge, but I am not too excited about having to disassemble the challeger to remove them to send them in. Hopefully, it won't be too difficult a project (the unit runs well now, I'd hate to mess up its performance).
If anyone needs more info you can check at:
http://www.nscalesupply.com/ath/ATH-challenger.html