I'm looking to change out the power window regulator in the tailgate of my 84 blazer for a manual. I found one in the tailgate of a 78 suburban. I've been told that these years will interchange, but we looked it up at the yard and the book says no. does anyone know if this regulator can be used in my 84? They look the same but i'd like to know for sure before I fork over the cash!!! Thanks!