There is no such oil as Dexron 4, there is Dexron 6 (VI).
Dexron 3 transmission cannot be used to replace Dexron Type A because they are not compatible. They are designed for use in different applications.
dexron 3 replaces dexron 2, so you could mix them but the dexron 3 is better
Dexron 3 or Dexron 4.
Dexron 3. User manual recommended Dexron 2.
Yes. Dexron III/Mercon automotive transmission fluid (ATF) is generally recommended as a replacement fluid for automatic transmissions meeting original equipment manufacturers (O.E.M.) performance requirements for current General Motors, Ford, other domestic and imported passenger cars, vans and light trucks where DEXRON II, DEXRON II-E, DEXRON III, AND Ford/MERCON fluids are specified.
The primary difference between Dexron 2 and Dexron 3 transmission fluid is in their formulation. Dexron 3 includes a number of corrosion inhibitors to prolong the life of components.
The major difference between SP iii and Dexron iii is the lubrication modifier. SP iii contains more lubrication qualities than Dexron iii. You can interchange the two but run a slight chance of premature wear using Dexron iii where SP iii is indicated.
Dexron 2 has been replaced by Dexron 3. If your Lebaron requires Dexron 2 then you can use Dexron 3. Never ever use a different type fluid than the manufacture requires, except is a case where the fluid has been discontinued and upgraded.
Dexron 1 was introduced in the 60's and banned in the 70's because it contained whale oil. if you can get your hands on a bottle, go crazy.
DEXRON II (as in "2")
dexron-mercon
Dexron 2 is called for in the manual but is no longer manufactured. The dealer recommends Dexron III.