I’m all for do it yourself mechanics, and have worked on my cars for a couple decades. That said I always pay pros for diagnostics of my issues now. Saves a lot of time and money. Pay them to tell you what needs doing, then dig in and do it. I imagine you have already, but if I was starting on that thing, that would be my first move. Good luck!
Discussion
Thank you. This is good advice. The fact that I will be replacing the motor and transmission with crate/new models (to ensure reliability and better gas mileage) after tearing this down and rebuilding it to get a hands-on education, and then doing the same for electrical and HVAC before I rewire everything and install solar, gives me a wonderful opportunity to see what I can do before I need to seek out a specialist.

