Glad I could help,Lionel also has a bit of loctite on the screws on the newer models as well.
I myself just checked the tightness periodically as the only way to grease the gearboxes on Lionmaster locos is to remove the screw and raise the motor up and the squirt some grease on the worm and inthe top of the gearbox.
Since you've been going through this loco,It might be a good idea for you to grease as well ( if you haven't already).
A little lucas red in tacky in there should be good for the life of the loco.
On a side note, I switched to full scale after originally collecting every Lionmaster loco. The class A was/is still my favorite, and the one I miss the most.
