For that engine, 3,000 lbs is not huge. I was towing 7,000 lbs on my 08 3/4 ton 6.0 engine, requiring 3,5000 rpm up grades. Under summer conditions ( and possibly higher oil temps) I switched to 5w40. Going back to 5w30 this fall. After 10 years of using synthetic 5w30, I’m closing in on 200,000 miles. Runs great.