Given the above cost benefits advantage analysis reasoning, I question just how much extra FoMoCo is actually saving by buying and storing carloads of Mercon just to dribble it into PS units at the company's various assembly factories. The chief reason I've been able to ascertain of not using Mercon V in ATs originally designed for Mercon is slippage from the more robust friction modifier package present in Mercon V. Given Mercon V's other advantages - speculated synthetic or near-synthetic qualities, and higher viscosity index for improved extreme temperature performance in ATs, I doubt the stuff's gonna be problematic in PS units. I also doubt the PS units give a flyin' fig about the presence of increased friction modifiers, either, since there aren't any clutch packs involved. My take is that for service top-up and changeout fill in the field, good ol' Mercon is good 'nuff, so the company cut owners some slack. But during initial assembly, the company probably sloshes Mercon V in at the factory out of convenience. If you're still a little confused about this issue, contact your Ford dealer's service manager for real confusion.
