4l60e trans. swap still doesn't shift
 

I have a 2001 pontiac, factory transmission went down and was replaced with a used transmission, car did not move. Replaced with another used transmission same issue. Replaced all trans. sensors. Need some help.

Any takers?

Just throwing this out there...broken shifter cable?? I had that issue and it was broken in near the shifter and the shifter would move but wouldnt shift gears.

Also, was the converter installed properly?

As far as we know the converter is correct. Have put in several of these transmissions and never had any problems. When the car is in neutral (on jack stands) the wheels spin at a high rpm forward. Don't think the cable is broken I am able to shift it manually. Im stumped. This is the second transmission (3 if you count factory) that I've put in the same car and it hasn't moved from it tracks.

The factory transmission was slipping when it was parked. This issue was not the cause for the transmission swap.

Any suggestions?

Even if the PCM was shot and/or the trans cable unplugged, it would start in limp mode which is 3rd gear. Are you sure you are not in limp mode? It takes a lot of gas to get a car moving in 3rd gear.
The rear tires might move slowly in Neutral, but should not be at "high rpm".
Perhaps the trans is in limp mode and the shifter cable is off by a bit, giving you a strange combination of problems.

Just throwing possibilities out there- Are you sure the rear end isn't broken badly? You can test this by seeing if the driveshaft spins while in Drive. If so and the car doesn't move then you have an issue in the rear diff.

Other than that, I don't see how you could replace the trans 3 times and still have no movement. That would be some REALLY bad luck.