Where do you add transmission additive to a 1992 Dodge Dakota?
same place you put the fluid, Through the dipstick hole on an automatic, through the filler plug hole on the side of a manual transmission it should be a hex type plug about 1/4 way up from the bottom on the left side.
Clearly Dodge Dakota, because the F150 can't go that fast with a little V6 or V8 and the Dakota has either a V6 or V8 magnum. Actually, the 1992 Dodge Dakota also came equipped with 4 cylinder engines, so without knowing which truck had which engine and which transmission and gear ratios each has, there is no way to tell which would be faster.
OK there are Three Engines in this truck. 1992 DODGE TRUCKS DAKOTA 2.5L 4-cyl Engine Code [G] Engine, with WIX Filter 51085..........4.6 quarts  1992 DODGE TRUCKS DAKOTA 3.9L 6-cyl Engine Code [X] Engine, with WIX Filter 51085..........4.1 quarts  1992 DODGE TRUCKS DAKOTA 5.2L 8-cyl Engine Code [Y] Engine, with WIX Filter 51085 ..........5 quarts  . After refill check oil level.