2007 Ford Mustang automatic transmission problems?

One morning I'm driving to go to work and all of a sudden my overdrive light on my console started flashing and my drive stoped working. I was able to pull the car over. I tried putting it in reverse and it wouldn't go. So now I see both drive and reverse are out. But the 1st, 2nd, and 3rd gears work. So now when I drive it I'll drive in 3rd gear and at about 45 mph I'm actually able to switch it to drive and the drive will start working. Can somebody please help me out by telling me what the issue may be? I would really appreciate it!

A flashing OD light is telling you there's a fault with the transmission and a code has been stored. You will need to have it hooked to a code reader to retrieve the code. This code will tell the professional where to start looking. Unless you are a transmission expert there's nothing whatsoever you can do but have this diagnosed by a professional. It is obvious you have a serious transmission problem so stop driving the car until you can have this repaired or you may do more damage than has already been done.

Reverse and drive not working at all means a internal problem. There's solenoids but reverse is not run by solenoids. Find local shop at ATRA.COM for more help might even smell the fluid any hint of burnt smell