Front Wiper Arms - Should they have splines? in Glass, Lenses, Lighting, Mirrors, Sunroof (BAMR), Wipers Posted December 22, 2021 · Report reply 31 minutes ago, omar302 said: On my 2016 Edge Sport, the motor shaft and wiper arm both have splines. I had removed the wiper arm a few times and can confirm it. Mine has splines on the arm side, but they look like they might have been made by tightening down the nut. If it had never spun, they would look pretty clean, I think.