2000 1500 lost all but first and reverse.

[Rjones]

Working on a friends 4l60e pwm. We have two transmissions the original was swapped with the other before the truck was purchased, and could only utilize 1st, 3rd, and reverse.
The truck eventually lost 3rd blowing the clutch pack. We rebuilt the original and put it back in the truck, but still only have 1st and reverse. All the solenoids were tested and gave optimal resistances. At this point, we've just been testing pcm circuits to the transmission wiring harness, but we're still lost because all of the circuits seem fine.
Any help on this would be greatly appreciated. Cant wait to get this out of my garage