Q: 2012 genesis 3.8 shifts hard. What cost am I looking at to replace transmission

The shift issue should be diagnosed first especially considering the low miles on the transmission. It would be unusual for a transmission with only 78,000 miles on it to require total replacement (versus on the vehicle service). Anytime you are having difficulty shifting you should check the fluid level and condition. If the transmission fluid level is too low (or too high) that can cause shift difficulties. Delayed or harsh shifts can be due to faults in shift solenoids, the valve body, or other hydraulically actuated and controlled components. Much of that can be repaired with removing the transmission from the vehicle. If you want a shift diagnostic, performed by a certified Mechanic dispatched by YourMechanic right to your location, please request a difficulty in shifting diagnostic and the responding certified mechanic will get this resolved for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.