On30 Heisler Problems

[John]

I have an On30 Heisler that I purchased about five years ago. At that time it was running perfect with sound decoder installed. I retired and moved next. Late last year I placed the Heisler on my new layout and it was completely dead. I sent it back late last year to Bachmann for repair. I was told that it was an almost complete overhaul to get it repaired. After returning again it ran perfectly but it was also dripping with oil everywhere. I just now put it on the track (DCC) again and it is running very badly and I am getting squealing noise in the mechanism. At first the wheels would not even rotate. After a half hour of running the wheels are running roughly with a lot of noise (no sound decoder currently). Is there something in these locomotives that degrades without running? It has always been in climate controlled conditions and stored in original box. I have not ever had this problem before with other locomotives? Any ideas?