26k on my '06 Sentra so decided to drop the ATF. Threw in three quarts of Castrol Import ATF and one quart of Nissan Matic D (had it in the garage). After the switch the 2-3 & 3-4 upshifts flare a little under throttle which it didn't do before, or to a lesser extent. Been looking around for some real Nissan Matic D fluid but can't find it on line and don't feel like paying $9/quart at a dealer. Can anyone recommend a good replacement fluid for Nissan Matic D that won't break the bank? Manual says Dexron III/Mercon is acceptable, but I'm wondering now since the problems with the Castrol fluid. Any Nissan guys out there?