2006 ford F-350 lariet dually crew cab

The 6.0 is loved when it is working properly. But alas, it is/was plagued with many problems. I would advise you to steer away, unless you're very familiar with what your getting, and can deal with it. Gotta be some sort of aftermarket warranty. Even with that, it may not be worth the headaches.

I'm fortunate enough to afford a new truck, and I love Fords, but if I was shopping in your price range, for that vintage, I'd look to the other brands for diesel, or find a V10 truck. Good luck.