I have 2 questions regarding my 2011 rdx; 1; I have almost 29,000 miles on this vehicle and i was wondering 1: at approx. how many miles should i do a coolant system flush and 2: at approx how many miles should i do a transmission fluid change?; keep in mind this when replying: I live in the very hot during the summer state of Arizona; thanks for any info, etc anyone can give me. 