Codes of p0740, p0758, and p1860, poor shifting and slipping?

I would double check the pin location. also, did you swap the PCM and complete wiring harness? Here is how the transmission should be wired. Here is a guide so you can check the wiring connections:

https://www.2carpros.com/articles/how-to-check-wiring

Check out the images (below). Please let us know what happens.

I checked the wiring and completed the wiring to the ECM. I did not swap out PCM. Is that inside the transmission?

Could there also be a mismatch of flex plate to converter? I did have to change out flywheel and remove spacer to ensure that the starter would match up.

Codes are 740, 758 and 1860.

The ECM was refreshed to the 6.0l. Also has a stage 1 cam.

The PCM is the same from the 4l60 just reminded at pins 42 and 79.

Sorry its Monday! You included the codes my bad. Yes, the PCM is located next to the radiator.

P0740 - Torque Converter Clutch Circuit Malfunction:

P0758 - Shift Solenoid 'B' Electrical:

P1860 - TCC PWM Solenoid Circuit Electrical

So, the wiring looks like it might be incorrect. I would remove the transmission electrical connector so you can match the colors the wires going into and out of the main transmission connector. Here is the location of the PCM. Check out the images (below). Let us know what you find.

So, I did check out the wires yesterday at the tranny. Moved original pin S to U. Created new S pin to ECM pin 79 and new T pin to ECM pin 42.

That's how I wired it. Is that wrong?

I am not sure how you wired it, I would double check the colors going into, and out of the main connector to make sure it matches the wiring diagrams I provided. Can I ask why you repinned it in the first place?

The harness is from the 6.0l and the transmission is a 4l60. Had to do the re pin from what I was told.

I would try putting it back to the way it was.