Stuck in limp mode with dtc p0700

The truck will shift from first to 3rd only if done manually but their is no overdrive. Also when truck is turned off then started up it is not immediately in limp mode it only goes into limp mode after I put into drive and attempt to accelerate. Also the speedometer does not work until truck reaches 25 miles an hour or so or the speed point that automatically locks the doors. I have looked for relays and fuese but no luck. I went to a junk yard and bought a used solenoid pack which also of course ment a new trans screen and fluid No luck. The trans looks to have three speed sensors one in the lower rear of trans passenger side. and two on the drivers side these two i also swaped with used ones. But not the third one. I replaced the rear differential sensor brand new as abs light is on but did not help and abs light is still on. Im stumed dont no what else to do. After searching google about this problem i found possibly hundreds of others having had the same complaint.

One other thing the codes are p0760 and p0700. P0760 overdrive solenoid circuit falure which is what made me swap the solenoid pack. HELP AND SUGGESTIONGS.