Many sources on the internet are claiming that the 2018 Mustang will get a new 10 speed automatic transmission, as reported by the NYM news reporter. This new transmission was a joint venture with GM. It will be seen in the 2017 F150 first. The 6 speed will no longer be an option. It is should improve performance and help with gas mileage. The price of the transmission is currently unknown. From the information out there , i believe that it will be an option on the refreshed 2018 Mustang. We wait for next seasons auto shows in LA & Detroit to see the 2018 and confirm the speculation.