Just got the B123 service message on my '13 MDX and I am debating doing it myself. The only thing that concerns me a bit is changing the transmission/transfer fluid. I've done plenty of oil changes and changed the rear diff fluid when it needed to be done, but have never changed transmission fluid before. Is it a fairly simple DIY on a Saturday morning, or should I take it to the dealer and let them do it? Also, if anyone knows where I can find a guide for doing it that would be awesome.