It's time to change my transmission oil. I've only done it once a few years ago ant at the time I got the Valvoline (red bottle). I went to two auto stores this week and they didn't have that specific brand. I was told I could use the Mobil equivalent (blue bottle). Apparently the D/M stands for Dexron/Mercon. Just want to make sure I got the right things. Also, can I mix the two brands? I have some left in the Valvoline bottle and I would hate to just throw it away.