Man that sucks about the transmission. With your luck on transmissions I don't if going to the dark side would be any better. I do agree that maybe a medium duty truck would be a better bet.
Several of us ran FL series about 20 years ago. Medium duties are a different world. If you don't like your local dealer service, you'll hate big truck service departments, at least back then. Half assed and half done seemed to be the order or the day. One of us had a Fuller Spicer FS6406 puke at around 40,000 miles. What I DID like, you can hammer on these things all day long without worrying about breaking stuff. They make one ton components look like light weight toys.
Even the highly vaunted NVG 5600 isn't immune from failures.
https://www.cumminsforum.com/threads/nv5600-to-fso6406a-6-speed-fuller.41978/
