During the filming of a scene where Denise Crosby hits Eddie Murphy in the stomach with a rubber baseball bat prop, Murphy was afraid Crosby would actually hit him instead of stopping about a foot away like all staged movie blows. She demonstrated her control on both Walter Hill and Nick Nolte to assure Murphy, but ended up hitting him anyway during a take.
Gregory Hines was the first choice to play the Reggie Hammond role but dropped out due to scheduling conflicts with Cotton Club, The (1984). He later did another kind of buddy movie in the form of "Running Scared" as well as the military thriller, Off Limits.
The original script was said to involve two cops minus the help of a convict. One of the reasons the script changed direction was due to Walter Hill first meeting Eddie Murphy during a taping of Saturday Night Live.
The T.V. version has two extra scenes. One featuring a walk with Nick Nolte and Annette O'Toole and a scene that occurs after the shootout at the B.A.R.T. Station between Cates and the Police Chief. The Chief tells him that Internal Affairs is on his back. Other scenes are extended by a few seconds and Denise Crosby is wearing a bra and panties in the T.V. version instead of being naked.