I did my 1st RHO oil change at 1200 miles, based on my experience with the Hemi. Let one go to 7400 miles & it burned oil & had blue start-up smoke by 25K miles. My 2nd Hemi, I changed the oil at 1000 miles & it never burned any measurable oil.
That being said, the oil that came out of the Hurricane at 1200 miles looked almost new. Didn’t send for analysis, so don’t know if that change was actually warranted. So, I’m calling it a “feel good” service.
Now, the rear differential…at 5000 miles, what come out surprised me. It looked worse than I could have imagined. Gloppy & filled with metal shavings, including a couple small nuggets of cast iron from the axle housing manufacturing process. Smelled really bad, too. If I were in your shoes, I’d do the rear differential as early as 2500 miles.