Which Oil Grade do I Need?

darsben wrote:
The answer is in where you go and how you travel. Since the 5W only comes into play in cold weather if your truck never sees cold weather such as in S. California, Florida or south Texas then the 5 will probably never come into play.
The 30 is okay all the time as it gives a higher viscosity at high temps. Remember we are talking engine temp not outside temp. So while the engine may start out at ambient temperature it will eventually warm up to operating temp. If you are towing the temp may go a higher than when not towing that is when you want the higher viscosity. The owners manual is the bible for warranty work so stick with the 5w30.