I am having trouble with my 2016 Hyundai Elantra’s transmission. I can shift into all my gears just fine except for drive. When I do it shifts Reilly hard or I would have to push my brakes and then press on my gas pedal to reve my car up to 500 rpms to have it slam in to drive to get it to go. Can anyone please help me out n let me know what the problem is? It is also an in closed transmission unit.