I have an 02 WJ with the 4.7.
There are 3 versions, the 99-2007 PowerTech wiht 235HP, the 2002-2004 4.7 HO 265 HP with higher compression,cams etc and the 2008+ with new 16 plug heads which bumped the Hp to 310.
For your 2006, use the xW-30, I would use synthetic and change every 5-6K miles or at least once a year.
Also change your PCV valve, run copper plugs and be diligent on the coolant, t-case, diffs, brake and PS fluid.
There are 3 versions, the 99-2007 PowerTech wiht 235HP, the 2002-2004 4.7 HO 265 HP with higher compression,cams etc and the 2008+ with new 16 plug heads which bumped the Hp to 310.
For your 2006, use the xW-30, I would use synthetic and change every 5-6K miles or at least once a year.
Also change your PCV valve, run copper plugs and be diligent on the coolant, t-case, diffs, brake and PS fluid.