One problem related to crankcase (pcv) has been reported for the 2008 Ford F-250. The most recently reported issues are listed below.
Excessive blowby polluting engine. #8 and #6 cylinders, rings heavily worn or damaged due to diesel regen contaminating lubrication and getting in crankcase. This is a very well known and unacceptable issue causing scored engine blocks and failure of engine and dpf and egrs.