Just curious as my owners manual Just says Mercon, and I wonder if it is MerconV, or if it is still the III.
Truck was built 6/97.
Thanks!

Should be Merc V I believe.

I put Castrol Mercon V into my 97 Mountaineer V8. It's a semi-synthetic blend. I haven't had any problems, and I recommend changing the filter while the pan is down.

Also, put tin foil over your exhaust, especially the cat converts. You WILL spill tranny fluid dropping the pan, and this will prevent that nasty smell.

should be merconIII.

There is no such thing as Mercon III. There is Type "F", Mercon and Mercon V. There is Dexron III, but that was used in General Motors transmissions. Don't beieve me? Go and try and buy a bottle of transmission fluid labeled Mercon III. Anyway, if you have the 5.0L in your Mountaineer the 4-speed automatic transmission calls for Mercon. If you have the SOHC in your mountaineer, the 5-speed automatic calls for Mercon V. Ford issued a TSB on 8/6/01 (# 01-15-7) regarding correct fluid to use in their transmissions. According to the chart in the TSB Mercon V should not be used in the 4R70W until the '98 model year. There is a statment on the TSB that states "A new automatic transmission fluid (MERCON(R) V) was introduced in 1997 for use in some Ford, Lincoln and Mercury vehicles. This new MERCON(R) V fluid is not used in all applications and is not interchangeable with others transmissions fluids that are currently used. Using the incorrect fluid may cause transmission or transaxle concerns."