I have a 2005 Ford Sport Trac. When I put in Drive it does not move. I put it in 2nd gear and the truck now moves. I put it in Drive after hiting 10-15 MPH it goes fine. Reverse is fine also. This happended suddenly, not gradual. Also I've been driving it like this for quite awhile and it's not getting worse. Is this a transmission problem or could it be an elctronic or control issue? I love the truck but so much to replace the transmission.