I have a 2004 Ram 1500 4x4 with 5.7L V8 (HEMI). The manual says the preferred oil weight is 5W30. What is the defference between 5W30 vs 10W30? Also, would I harm the motor by using 10W30? I live in the Midwest (St Louis) so we have hot/humid summers and cold winters. I occassionaly tow and light Aluminum hull bass boat as well. I mainly drive highway miles.