The trans is most definitely an 46RE. And it is definitely a 96 production model. At this point, I suspect maybe it was an early production 96..

The good news is it now WORKS. The OD has cut the 70 mph rpm by nearly 1,000 rpm, it happily cruises along at about 2,000 at 70 mph on the cruise control where last Sat night on the same road, it wanted to turn 3,000 at 70 on the cruise control. I knew it was fixed as I pulled out of my driveway. Before it was sort of lazy leaving a stop, but now that it s downshifting, its back to being fun.

First what happened, and then the fix.

When the truck was 1st put on the road, I used the Dakota aluminum/plastic radiator. I had to modify the top radiator brackets for it to work, and both top corners were very close to the 49s curved hood sides. About 6 months into driving the truck (its 1st winter), the OEM Dakota radiator started leaking at the gasket between the top plastic tank and the aluminum core. It actually would not leak if the temp was above 15 degrees, but when it dropped below 15, it started seeping. The leak would go away shortly after the truck started. It took a few months before I actually saw where the coolant was going when I happened to look on a day it was 10 degrees outside.
I changed to a Champion aluminum radiator that better fit the confines of the truck, but that required the removal of the manual fan because of clearance. I installed an electric fan with the new radiator. While I was looking for a power source for that electric fan, I noticed the distribution box had a "fan relay" that was not being used, because there obviously was not an electric fane on the truck. I hijacked the key source 12 volt power wire from the fan relay to run my electric fan. The radiator replacement also required a moderation in the transmission cooling line routing. The new radiator was a crossflow with the trans cooler on the passenger side, the original was a top to bottom flow with the cooler in the lower tank. About 3 or 4 weeks after the radiator was installed, one of the trans cooler lines blew the hose off. I didn't know it until the truck stopped moving (about 3 miles from where the fluid trail began). I did a parking lot repair on the line, and dumped 8 quarts of AFT +4 into the trans. The trans appeared to operate OK except I noticed the OD was not functioning (the weather was warmer and we were doing more driving). The consonance here concluded the loss of the trans fluid killed the OD solenoids and probably caused deadly transmission problems. I accepted that and was waiting for a total failure, pulling this trans will be a major pita.

This post alerted me to the concept the fluid loss might not be the cause of the OD loss.

The fix: After spending much of yesterday looking for the missing trans relay, I was prepared to create a fan relay from scratch this morning, but the thought that the OD worked when the truck was first put together pushed me to find that missing relay. In my search for the trans relay, I began to wonder if one of the relays was mislabeled. The most obvious choice was the "fan relay". With the plugs off the trans, and the distribution box pulled up where I could check out the wiring, I started checking where the existing wires on the fan relay went. 4 wires. One (already cut) was a 12 volt ignition source. One was a battery power source. Both required for the trans relay. One wire was a 5 volt from the computer (required for the trans relay, but not required for a fan relay). The other wire had continuity with the #1 terminal on the trans connector (also required for the trans relay). My conclusion was, Mopar decided to use the 95 distribution box on the early 96 trucks, and substitute the fan relay that was only used on the 4 cylinder trucks as the location for the new trans relay. Not a bad idea, but they should have told at least their service department.

I restored the 12 volt ignition source back to the relay and reassembled the truck, and the OD works, and the trans also downshifts and upshifts. In a couple weeks we will run the codes again and see if we still have any transmission codes. For right now, I am a happy camper.