Being 2017 does it have Kia warranty still? It's normal to have play in the diff. Maybe the issue is the auto box itself if it's a delayed harsh engagement or put up a video of your car.
Any drivetrain vibration at speed or grease escaped from the inner boot? If you're convinced it's the shaft , pull it out and check inner joint for excessive lay. These joints slide in and out so when they do wear it'll be in one area where they operate. If the joint is fully in or out it will probably feel fine.
Any drivetrain vibration at speed or grease escaped from the inner boot? If you're convinced it's the shaft , pull it out and check inner joint for excessive lay. These joints slide in and out so when they do wear it'll be in one area where they operate. If the joint is fully in or out it will probably feel fine.
