I just installed a 2600 rpm stall converter in my 4l65e and have a few questions. The truck shifts alot softer from 1st to second, do I need Nelson to retune to correct? Also I didn't buy enough Dexron 3 and had to use Ford motorcraft Mercon V to finish filling(both non synthetic). About 13 quarts was needed because of my 2 quart extra deep pan, 5 of which were the Mercon V. Are they compatible with each other or do I need to drain and refill? From looking at the back of the cans they looked compatible with one another, just one is Fords name and the other is GM's version. Please help!!!!!! I don't trust the idiots at the auto parts stores!!!!!