Superceed may not have been the best choice of wording. Retroactive? How about "Each subsequent classification meets the requirements for all previous classifications"?
Therefore: SM covers everything before it. As does the SL and SJ classifications. They cover all classifications that came BEFORE them. In some sense, they do supercede, but...maybe "replace" would be a better term.
In this case, all of those classifications cover SF and even beyond that, there is nothing on the shelf of your local auto store that will not cover SF. Heck, I doubt you could find anything rated lower than SJ, or even if you can find SJ. Small, hole-in-the-wall, mom-and-pop stores are excluded from this.: <img src="/forums/images/graemlins/smile.gif" alt="" />
As for being flip, that was not my intent. Regardless of the search for information and the discussion of rather minor minutia, common sense must be considered. The bottom line is we are working with a transmission that is 20 years old. Any 5W30, fluid bought today will fit the bill.
To further put this discussion in some perspective, the API certifications are for engines. Not transmissions. Oils used in a transmission require much less additives and stabilizers than when they are used in engines. In the case of the Isuzu transmissions, viscosity becomes much more important than anything else because of the need of oil to reach some of the farthest bearings. That is why gear oil kills MUA5s dead.
So, I'll say it again, with less flip: Just go buy some 5w-30 and be done with it.
Michael
