Ford Mercon-V is a semi-synthetic not a 100% full synthetic.
There are other oil companies that make a 100% synthetic Mecon-V...I have used Pennzoil, but other brands will work as well as long as they meet Ford's Mercon-V spec's. That's what spec's are for. Also, don't let anyone claim that Ford does not recommend the use of any specific fluid...Be sure to see that in writing from a trusted Ford source...That is illegal unless Ford is willing to pay for your fluid changes...and they won't (part of the Magnuson-Moss Warranty Act).
I don't have any axe to grind and I don't sell lubricants so I never recommend a particular brand, but I do not recommend Universal fluids that claim one fluid fit all manufacturer's specs...Nor do I recommend fluids that claim they can be made universal with the addition of any special additives to be compatible. I only mention Pennzoil's Mecron-V because I know it is 100% Mercon-V spec compatible and it works. I have used it in both of my Sport Tracs and have never encountered any problems, and that's not saleman's hype, it's a customer testimonial.
I will recommend a fluid flush to replace about 98% of the old fluid rather than just a standard fluid change You can drop the pan and replace the filter if you want, and then do the fluid flush. If you do not do the fluid flush, you will only replace about 50% of the old tranny fluid.... and it may take 4-6 fluid changes (of 50%) to get nearly all the fluid changed that a Fluid Flush can do in just one shot.
Synthetic and Semi-synthetic Mecron-v should all be 100% compatible between brands, but a fluid flush illiminates and guessing by just replacing nearly all the fluid, not just half.
...Rich