If you don't mind going up north about 30-miles or so to Sunbury, you can check out Wilson RV. They do both house repair and routine chassis maintenance and repair (engine, transmission, suspension etc.). I'm not sure if they will do engine or transmission rebuilds or replacements but I'm sure they could refer you to someone who could if needed and they can't take care of it.
RV Service - WilsonRV
I was referred to Mike several years ago by somebody who recommended him when I was having a slide problem and they fixed it fast and for a reasonable price.
I could only find one review from a few years ago on RV Service Reviews .com but it is a nice one ...CLICK here