I just bought a nice used 94 Supra TS6M with the PCM transmission. The owner's manual states that 20-20w SG rated oil should be used in that tranny. Discount Inboard Marine says that Dexon III transmission fluid is now recommended for all PCM transmissions. I have been unsuccessful at finding straight 20 weight oil and am tempted to go with DIM's recommendation. What does everyone else use???