Update on steps problem.
Thanks for all of the replies. After I had ordered and installed a new motor and drilled out larger holes for the new bolts into the motor casing, everything worked like a charm. No more loud grinding/growling noise and she works good!
When I opened up the old motor, I did notice a lack of lubrication and I suspect that the screw gear was grinding on itself inside the housing.
As well, there are not a lot of places to apply lubrication, especially when the moving areas are all exposed to dust, dirt, sand and whoknowswhat as you travel down the highway. Last thing I want to do is to add some grease that will only attract more grime inside the large gear area which moves the step inside and out. I think, though, that I will add this area to my list of places to inspect and clean well each year.
Thanks again for all of the replies!