There is no such oil as Dexron 4, there is Dexron 6 (VI).
one is for gm and mercon is ford now days they make a dexron mercon mix acceptable to both Dexron III and Mercon V have different specs. You should not use Dexron III in place of Mercon V.
Dexron 3 or Dexron 4.
MERCON V is a transmission fluid for Fords and DEXRON-VI is a fluid made for GMs. Mercon and Dexron are NOT, nor have they ever been, the same thing. People got the idea that they were because traditional ATF meets the specs of both. It doesn't mean that they have the same specs. Mercon V and Dexron VI are non-interchangeable. Always read the label of any ATF you plan to use. GM, Ford and Chrysler all use different fluids so make sure that what you choose is correct!
specs 4 what?
Depending on the transmission type, a 1992 Volvo 940 requires: Automatic transmission: Dexron III (technically, Dexron II, but most brands on the market these days are all upgraded to DEX III). Or, you can also use Volvo's OE brand of automatic transmission fluid, which of course meets the specs of Dexron II/III. The fluid capacity is 2.2 quarts. 4 speed Manual transmission: Type F (2.8 quarts) 5 speed Manual transmission: Type F (1.6 quarts)
The difference between dexron 3 g and dexron 3 h is that dexron 3 g is used to be the factory fill quality. Dexron 3 g was the requirement for service fill quality.
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.Dexron VI is a partial synthetic which properties exceed dexron III by 100% in every area. Dexron VI can not be interchanged or repalced with DEXRON II, DEXRON II-E, DEXRON III, DEXRON-III/MERCON.
Dexron 3 transmission cannot be used to replace Dexron Type A because they are not compatible. They are designed for use in different applications.
Use Dexron-VI. This replaces Dexron II which was formerly used in your S-10.
dexron 3 or 4
4 bottles (quarts) of fluid. I have a 1999 XLS, & I recently changed transmission fluid. Transmission was drained with removing coolent connection etc. (complete removal). I Dexron VI can be used, instead of the original Dexron III (original fluid - again Dexron III was a cutting edge when 98 Avalon was released!). Dexron VI has many advanges over Dexron III. Consult a knowledgeable mechanic, & use the proper Dexron VI for your vehicle.