Mclasser--
It's tough to judge the condition of gearcase oils visually. The oil will suffer from thermal breakdown, but only when temps get high from metal-on-metal operation (what the oil is trying to prevent), from very high loads (tough to achieve in the Pilot), or from transferred heat. There are no combustion contaminants. The oil can get slightly darker color in service if there's local hot-spotting inside, still hard to judge visually without sample tubes of old and new side by side.
In theory, the oil in the gear case should last the lifetime of the car so long as there are no leaks. Same theory that ZF/BMW, Chrysler, and some other specialty car manufacturers use to justify "lifetime" ATF with no easy change capability. That said... Gearcase and differential oils in my cars get changed on my aggressive 15k ATF replacement schedule. Except for the fragrance, there's no reason not to change it "just to be sure". I'm under the car with the drain can anyway.
Gear oils, when they are part of a gearcase failure, end up carrying metal particles around so that every moving part of the assembly gets to share in the failure fun. There is no particle filter. The oil should therefore be sampled for particulate contamination (pass some through a clean white towel) and replaced if there is -any- evidence on the towel. Meanwhile, the effort to drain and sample is about the same as drain and replace. The oil is cheap in the giant scheme of things.
Virtually any synthetic gear oil will do the job nicely. As others mention, Mobil-1 is readily available at most parts places. For the duty the Pilot places on it, there's no real need to find a more exotic oil or additive. Decades ago I received sponsorship support from Bel-Ray, including what's turning out to be a lifetime supply of their synthetic gear oils, so I use what I have. I like a couple of the Redline products in the German touring car, as I can "tune" the action of the limited-slip final drive unit with the ratio of friction modifiers in the two oils. That's not an issue in the Pilot, which uses selective brake application to manage low-speed slip. Bottom line is that any good synthetic gear oil will be more than adequate in the Pilot.
