Any fluid besides ATF+4 can cause shift quality issues.
Mercon is an additive to Dextron atf
Mercon/Dexron or Mercon VI.
You can use ATF+3 with all older Chrysler transmissions. Do not use ATF+4 Dexron, Mercon, or any other fluid.
Automatic trans fluid has three basic types: Mercon for older Fords, "Dexron plus three" for Chrysler and plain Dexron for everything else. You need ordinary Dexron Automatic Transmission fluid
You want to use MERCON V transmission fluid. Do not use MERCON/DEXRON III as this older version is not formulated to operate correctly in your transmission. The bottle must clearly specify MERCON V which has superceded the older MERCON/DEXRON III formulation.
Mercon/Dexron III
my husband has a 1998 dodge truck and he uses GM Dexron-III/Mercon Automatic Transmission Fluid. You can buy at any automotive store. Dodge,Chrysler and Jeep products require ATF + 4 made by Chrysler. While it is okay in a pinch to top off with GM Dexron-III/Mercon, replacing it with that will cause you problems. They are different.
Mercon, or Dex/Merc, or Mercon V. MOST fluids marked Dexron/Dexron III are also Mercon certified.
Dexron/mercon
It will take dexron or mercon
Dexron/Mercon ATF
dexron/mercon