Is your ABS cable still disconnected? If not, disconnect and clear codes and see if it will stay out of failsafe. I know you disco'd it...but if you didn't clear the codes after disconnecting it...the ABS can still interfere. I'm the guy who had the 4.6 that would go into transfailsafe at 71 mph (and reproducible). I chased gremlins for almost a month until I looked at the Car Area Network diagram and realized the ABS and EGS could speak via the CANbus and DME. I pulled the ABS and cleared the codes and no more Trans Failsafe. Sent my ABS out for repair and all was well once I reinstalled it. Just my experience and would suggest you at least try it out. Best of luck to you!
