diesel maintenance questions

I keep my maintenance records and UOAs. My last CTD truck had 94k miles and was 9 years old. I sold it in 2 days sight unseen for $5k more than compatible gassers were bringing. That's resale value! I don't know of anyone beside me who tried a gasser class 8 running 80k lbs. It was a 549 IHC with 5x4 boxes and I got 1.5 mpg loaded and 3 empty. I was shifting every 20 seconds and it wouldn't outrun a cow. There's no question which is better for heavy work. Craig