One problem related to transmission not go into gear has been reported for the 2015 Ford E-450. The most recently reported issues are listed below.
This is a school bus. When stopped at a stop sign the school bus would not engage in any gear, forward or reverse. The school bus had to be towed to the Ford dealership where they found that the coast clutch drum, return spring, piston and one way clutch needed to be replaced. This is the 4th school bus we have had this issue with.