"Detent" means the click you feel and hear when the transmission (or shifter) is in each position (P, R, N, D, 2, 1). If you were to disconnect the shift linkage and operate the lever on the transmission by hand, you would still feel each detent. You would also still feel each detent in your shifter. Your task, should you choose to accept it, is to adjust the linkage so that both align. If so, the linkage should be slightly free at each position.