the 6.7 issues that were mostly on early 2011 6.7 have all been fixed with updated and the current 6.7 has proven to be the best Diesel Ford has produced since the 7.3. There is like anything a possibility of issues in your fuel is contaminated and this gets blown out of proportion all the time by many folks here and elsewhere - bottom line don't fuel up in shady gas stations and keep receipts when you fuel in case it does happen to you.
I'm on my second 6.7 and have yet to run into any issues that are drivetrain related - just the usual wear items that need to be addressed.
