gears

So I picked up a Joshua Cowen 6-8210 4-6-4, and the drive gears are obviously in need of change, how tough of a job, how available are parts ? Made in 1982 I know I'm up against it, maybe have to buy similar with bad shell and swap out? Thoughts?

Hi, I have just purchased my first ho diesel brass locomotive, a consignment model. I would like to oil and grease the necessary parts, and service it, how ever there are no instructions on how to take the model apart to expose the gears or what oil/grease to use. Can someone point me in the...