Please excuse me, but have I missed something? Is there really anything wrong with this truck, other than the first mechanic saying that, ahem, something was wrong with it? And then in the same breath he wanted to buy it? C'mon, that is the oldest trick in the book. My advice is to download the Technical Manuals (a.k.a. TM's) free from this site, read them and learn about your truck. Then check all fluids to make sure they are at specified levels, and enjoy the ride! There is no way I would start tearing things apart just to be tearing them apart. Not sure where you are located in Kentucky, but I am in Paris just north of Lexington, and if you will drive it here I will be glad to check it over for free. I have no secret motive to buy your truck because I already have one which I would not trade for any truck on the planet. And I sure will not suggest unnecessary repair because I don't do repair. Just willing to help out if I can.
Hope this helps.