I have an Outlook, which is essentially the same vehicle. GM even went back in time, and took the backend of the old outlooks and put them on the new Acadias.
I wouldn't go crazy changing the fluids on this car too often. Most hold up pretty well, while others need a little more attention. You'r schedule is a little aggressive and may not be worth your time and money. But that's my opinion. Watch the oil and the rear dif, but the others aren't going to give you a lot of problems.
Personally, I think 2k on the factory fill oil is a little soon, if you are planning to go right to syn. I would refill with dino for the next 2-3 OCIs or more, and then switch to syn, but thats my opinion. used oil analysis in this forum and others show that this engine will shed iron for a while, regardless if its filled with conventional or synthetic. Let the break-in happen and keep the oil clean with frequent changes and a quality filter. I do not have the DI engine, so the Oil Life Monitor will take me to 10k, if I go based on that. I usually run it to about 85-90%. I do have to add about a quart of makeup oil along the way. The water temp at operating temperature is 210, which means the oil is at least 250. I would recommend an oil with a low NOACK.
I do think an earlier swap of the rear dif is a good idea. I did a drain and fill of the front and rear dif at 75k, and while the front was still pretty clean, the back end was very dark. I would reccomend not going over 50k. The front dif is a little more difficult to do. I think you are supposed to drop the exhaust to get to the fill plug, but I fashioned a tool made out of a 10mm allen wrench and a 10mm socket to get the job done.
The transmission fluid was still looking good at 70k when the dealer did a flush as part of a repair that had to be done. It was a dark cherry red, which was to be expected, but not black or brown. The fluid change is easy. The "pan" (there really isn't a pan) has a drain plug, so its easy to do quick fluid swaps. When my Outlook hits 100k, I am going to start doing drain and fills every 30k miles or so. That way at least half of the fluid will always be new every 2 years. There is no easily serviceable filter on this transmission. You have to remove the transmission and tear it apart to get at the filter.
Good luck with the new Acadia!
