I have a 72 Suburban that I fully restored a few years ago. Has a 350 with reputably built late model TH700R4 behind it. Drained the Coastal Dex III ATF that was in it yesterday and filled with fresh Pennzoil Dex VI. I put about 30 miles on it today. I may be imagining things but it seemed to shift smoother and a little sooner than before. I am pleased.