I have a La115 John Deere tractor with a B&S engine. I have been using pp 10w30 for the past few years. This year I decided to used Rotella T 10W30 because of possible improved wear protection. My question is this. John Deere recommends 10w-30 or 10w-40 for summer time temps, could I use Rotella T6 5w-40 for outside temps from 32F to 100F? If not, what would you recommend.