From Wikepedia:


Basic RFE operation[edit]
The fully electronic control is accomplished by the Transmission Control Module (TCM). Depending on year and application, it can either be a stand-alone module or integrated with the Powertrain Control Module (PCM). The TCM uses data from various transmission and engine sensors to control transmission shifting. The transmission operates the solenoid pack to change hydraulic flow through the valve body to various clutches in the transmission. The solenoid pack is mounted directly to the valve body; its connector protrudes from a hole on the left side of the transmission. On the 45 and 545RFE the hydraulic control system design (without electronic assist) provides the transmission with PARK, REVERSE, NEUTRAL, SECOND, and THIRD gears, based solely on driver shift lever selection. This design allows the vehicle to be driven (in “limp-in” mode) in the event of an electronic control system failure, or a situation that the Transmission Control Module (TCM) recognizes as potentially damaging to the transmission. On the 68RFE, fourth gear is used for limp-in instead of second and third.

This might explain things. If the trans is designed to still operate in reverse, 2nd and 3rd in the event of an electronic system failure then I must have an electrical gremlin. The truck did feel like it lost first and overdrive. I did not know until today that it IS double overdrive with a 4th gear .75 and a 5th of .67.