Join Date: Feb 2008
Before you begin tearing it down, try pouring a little marvel mystery oil in the crankcase. Drive it for a day, then change the oil again. See if it stops.
That said......sometimes even a brand new 4.0 will sound a bit like a diesel engine at times. Both of mine have, every once in a while and I bought them both new.
2007 5.7 Hemi, Ltd. QD II -
1997 ZJ, 4,0 select trac, Up country, track lok.