Whatever Ford says to use for that model year.
Motorcraft MERCON automatic transmission fluid is used in the 5 speed manual transmission of a 2000 Ford Ranger according to the Owner Guide
It possibly could be a bad alternator.
C4 transmission
Model 4R55E automatic transmission
If they are of the same model.
AOD
The Ford 3430 typically requires a transmission fluid that meets the specifications of Ford M2C33-F or M2C134-D. Common choices include Type F or Mercon automatic transmission fluids. Always consult the owner's manual for the most accurate recommendations regarding transmission fluid for your specific model and year.
No , starting with the 2002 model Ford Explorer ( 4 door ) there is no dipstick for the automatic transmission
No, there are plenty of older model Ford trucks that are standard transmission.
any kind
A4LD automatic transmission