Yea man, you say you got it for free? How can you expect it to be a cherry? No one gives away anything good.
Yea go get one of those **** bucket GM diesels. You want to see a real piece of crap that breaks down all the time then go get one of those. Why do you think they are so rare to see on the road? Because it was too hard to keep them running.
And by all means go get one of those true Found On Road Dead PSD's. When one of those break, you HAVE to break the bank, or rob one, to fix it. Just one injector for a 7.3 power stroke will cost you over $300 from Ford.
I for one can vogue for the fact that the International IDI is THE BEST diesel engine ever made when it comes to longevity! My grandpa bought a 1983 F250 with the first design 6.9 in it. We drove that thing until Nov 2006, the day it died from a rollover. It had over 650,000 miles on the original engine, with the original glow plugs, with the original IP. The speedometer broke about 6 years ago and it had calculated 580,000, and we drove it every day after that with the speedo broke.
I dont know what to tell you about your truck, I dont know what all has gone wrong with it. But with my family now having 7 of these trucks, I know for a fact that they do need regular service or they will never forgive you for it.