The 2005 Honda owners manual states VTM-4 fluid changes at 15k miles, 30k miles, then every 30k miles for “normal operating conditions.” The “severe operating conditions” change interval is every 15k miles. Severe includes Canadians and those who regularly operate their Pilots at 90F degrees ambient and above.
I’m not sure how the maintenance minder system (2006 and beyond Pilots) factors the weather into the calculation for when service is required, but the 2005 maintenance schedule is a good reference point.
For the chattering in the rear differential, if you used a fluid pump that previously pumped non VTM-4 fluid that may have contaminated the fluid. I have read that on numerous posts in this forum over the years. Your VTM-4 fluid pump should be dedicated to this fluid only. I have performed six VTM-4 drain and fills, over the years with a dedicated fluid pump, and the rear differential has never chattered.