I think the point here is that the Ford 6R60/80 transmission was actually a ZF 6HP26 made under licence by Ford in Livonia. That’s why it’s not unreasonable to speculate that Mercon SP, which was specified for the 6R60 (and made by Shell in the USA), is identical to ZF LifeGuard Fluid 6/Shell M1375.4 (made by Shell in Europe).

When Ford replaced Mercon SP with Mercon LV some time ago there was a lot of discussion regarding LV’s backward compatibility with SP and whether it was causing issues with the performance of the 6-speed.

So is Mercon SP still available in the USA?

Phil