D Doss Guest Jun 2, 2008 #2 3d is 3 speed 4d is 4 speed. if your in d3 it kills your engine real quick if your high speeds d4 is made for when your going in 4th gear.
3d is 3 speed 4d is 4 speed. if your in d3 it kills your engine real quick if your high speeds d4 is made for when your going in 4th gear.
