I would change the oil at 500, 1000, 2000, 3000 and then every 3000 miles after that. After 3000, change to synthetic. That's just me, but I think the break in period is critical. You might also check on a bypass filter from Amsoil or Oil Guard. Also break it in nice and change your differentials at 500 miles then every 10,000 to 15,000 miles. Also your tranny every 10,000. Mag Hytek makes nice differential covers that you can change the oil very easily. There are magnetic dip sticks and drain plugs to suck up the metal shavings. You will be surprised after 500 miles how much metal shavings are floating around your diffs. The magnetic dip sticks and drain plugs will collect most of it. Don't listen to the manufactures recommended 100,000 on the differentials. It's rediculous. Every 10,000 to 15,000 with synthetic gear oil, probably 75W140 in the rear and 75W90 in the front.