The fluid should be replaced when worn, you will hear "rubbing" or "moaning" on sharp turns indicating this...it begins on the first turn of a drive (pulling out of a parking space for example) but later it can be heard on any sharp turn. Turn off the radio and listen.
The 2005 & up V's have a cam actuation mechanism in the rear diff that actually makes the fluid wear out sooner. I started hearing the moan at 14K miles on my '06.
It's easy to change: on your 05, remove the charcoal canister cover (three bolts), open the fill and drain plugs (in that order!), drain and refill with 1.3 quarts of Honda Dual Pump Fluid.
DON'T use anything but DPF in the diff. Like Honda's ATF, it is a special formulation for Honda clutches. You could save money by having the corner gas station change the diff fluid for you (takes 10 minutes on a lift) but make sure they have the Honda fluid...offer to supply it if necessary.
I don't think that is true, Honda factory-fill motor oil has a moly additive in it so they want you to keep it in the engine at least 5K miles, but I have never heard of anything special about the ATF factory fill.
Remember that a drain & fill on the Honda ATs only gets a third of the fluid out each time...so if it's "used to the fluid" that's in there, there's STILL a lot for the trans to be familiar with...
I think 10K is rather like overkill on ATF fluid replacement, I have had no problems using the factory schedule (every 30K) in my Acura which has 120K miles on it.
HTH
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