Just wondering if any knows definitively if Toyota T-IV is backwards compatible with Dexron III. The reason is I am changing out my tranny fluid and thought I would also do the power steering pump change as well, but if possible use T-IV fluid instead of Dexron III. I like the idea of having one oil for tranny and PS pump, one oil for diffs/transfer, one oil (Delvac 1 5-40) for engine/car/mower etc. saves having 14 half empty bottles of different fluid in the cupboard to get mixed up and put in the wrong thing. (I remember many years ago Mobil brought out an oil called Mobilland Super Universal, one farm, one oil, suits engins, diffs, transmissions, hydraulics etc. They stopped it so I guess some things blew up and they got sued?) I would howeve,r like to reduce the number of oils I carry.