Yes, it is an appropriate fluid. When your car was built, Ford called for Mercon ATF to be used in your trans. As far as I know, all ATF that meets GM's Dexron III spec is also labeled that it meets Ford's Mercon spec.
There are better answers though. You will greatly improve overall shift quality if you add 2 oz (half a bottle) of Ford XL3 friction modifier.
You could have also used Chrysler spec ATF+3 fluid without friction modifier with the same result. The Chrysler fluid has a higher level of friction modifier in it to begin with.
One of the more popular fluids is the so called "cocktail" of synthetic Mobil 1 ATF with 2 oz of Ford friction modifier added.
Starting in very early 2000, Ford started using a manual transmission specific full synthetic GL4 gear oil. It is often call "Ford Honey". Ford says that is is suitable for replacement or top off on any MTX-75 trans. It is great fluid, but it is a bit pricy. It also works best with the addition 2 oz of Ford XL3 friction modifier.
Many that post here on the CEG report that they have had good results with RedLine synthetic. RedLine has two products that will work. One is more like the consistancy of ATF and the other is a little heavier more like gear oil. Some say that it works fine without adding friction modifier and others say that it works better with friction modifier.
Personally, I have used plain Mercon (without friction modifier), ATF+3, and the Ford Honey with friction modifier added. ATF+3 was a huge improvement over Mercon without friction modifier. Ford Honey with friction modifier is slightly better but hardly worth the additional cost.
If I were you, I would add friction modifier to the trans now, and when it is time to change it again in 30,000 miles I might try something else. A synthetic fluid would be especially beneficial in a cold climate.
