Can i use ATF dexron3/mercon in power steering reservoir in my '04 toyota 4runner. owners manual calls for dexron 2 or 3. i don't know what mercon is.
Yes, a lot of power steering pumps call for automatic transmission fluid (ATF) instead of traditional power steering fluid. The difference between the two fluids will vary between brands, but has to do with a difference in cleaning, lubricating and hydraulic characteristics. Often if the wrong type is used, the fluid will eat the seals in the power steering pump and rack and pinion system. MERCON is Ford's ATF certification program.
Along with the owners manual, the power steering reservoir cap will say what type of fluid to use.