Yes, KOEO transmission in park and in drive yielded the same voltage to all 4 terminals (14v), connector plugged in, back-probing them

 

Ok, so we know that the PNP is not sending the correct Transmission Range selector signals. So at least we have a dead end to the problem. Possible it could be an adjustment issue. But I might try putting in a known good switch since you have one (the new one) to rule in or out the switch itself. I'll look in the meantime to see what else could be checked, but my gut is telling me that the problem resides with that PNP switch somehow.

 

You will need to do any voltage checks on the Transmission Range switch by back probing and the connector connected. There is 4 switches that supply ground to each pin depending on the position of the shift selector. So checking it with the connector removed will show HI voltage on the harness side coming from the PCM.

 

So I have this theory based off of what I'm looking at and I'm not going to go so far as to recommend it because there is some safety issues to consider. I would only try this with all four wheels off the ground, and the vehicle securely raised so there is no possibility of the vehicle coming off. A second person would also have to be in the vehicle.

So the four wires going to the PNP/Transmission Range Switch C1 have ignition voltage being supplied from the PCM. Depending on the different grounding configuration of the four internal switches in the PNP tells the PCM what gear has been selected by the driver.

My rationale is that if I were to disconnect the C1 connector and ground the the appropriate cavities, then the transmission would go into the gear that corresponds. This would inform me that the transmission and the PCM are good to go and shrinks the problem down to the shifter/PNP area. Here's how I would do it:

1. Truck very, very securely raised with all wheels off the ground and a helper in the drivers seat.

2. Disconnect C1.

3. Configure/ two wires that could create a ground for C1 cavity "A" to known good ground (BLK/WHT wire) and C1 cavity "D" to known good ground (YEL wire). BUT DON'T GROUND AT THIS STEP AND KEEP WIRES ISOLATED SO THEY DO NOT TOUCH THEMSELVES OR ANYTHING ELSE! Remember, these are connected directly to the PCM and have voltage running through both of them. Leave the other two cavities (B & C) open not connected to anything. Note: I referring to the harness side of the connector C1 which is disconnected from the PNP. Nothing gets done with the PNP side of the C1 connector.

4. Have assistant start truck and keeping foot on the brake shift into reverse. Slowly release brake. Nothing should happen.

5. Foot back on brake, still in Reverse, ground the two wires to known good ground at the same time (keeping them separate). Do not touch/short wires to each other.

6. Slowly and lightly assistant takes foot off brake, trans should have engaged in reverse and wheels should start spinning.

That's my theory. Basically selecting reverse by supplying the ground configuration for the "Transmission Range Logic". May not even be necessary to move the shifter into reverse, but better I believe just in case. Theoretically, there is only one element for the system that I would be manually applying. That is the correct TR Logic ground configuration for Reverse. (Cavity "A"=LOW; Cav "B"=HI; Cav "C"=HI; Cav D=LOW)

BUT BEWARE, the wires go directly to the PCM so if I'm missing anything, you could fry the PCM. I would think two or three times before doing this. If it was my own truck, I'd do it. But I'm not comfortable enough to actually recommend on someone else's.

 

Attached is what I am basing my theory on. Please note that Pin/Cav location and TR Signal locations do not exactly correspond:

Pin/Cav A = TR Signal A
Pin/Cav B = TR Signal C
Pin/Cav C = TR Signal P
Pin/Cav D = TR Signal B

 

In post #22 you stated that you can shift but transmission just revs like it is in neutral. You have more than an electrical problem. The transmission will move in forward (3rd)and rev with no electric to trans. How much fluid did it take to fill after replacement? If you pull the dipstick without engine running is the fluid above the full mark?

 

Cool, an expert. Good to know about third and reverse. Learn something new everyday.