Did you remove the plug in the torque converter? Did you put it back in? Not even sure this would totally disable it but thought I might mention it.

Do you have any ideal of how much fluid you put back in. I do not know if you could trust the indicated fluid level in your situation. The average amount of fluid needed is known if the torque converter was drained and if it was not. How much fluid did you put back in? So that would lead me to wonder if the true amount of fluid is lower than what it should be. I think for example a couple of quarts low just might produce a non functioning automatic.

Other than some form of fluke failure. The odds of it being being very low. If the transmission was operating normally before the change it should be okay. Personally I suspect you filled by the dip stick measurement only and the torque converter may be dry as the fluid level is too low to pick it up. Bearing in mind I know very little about automatics.

Posting how much fluid you installed and if the torque converter was drained or not may go a long way.

If the transmission is not actually working the torque converter cannot get fluid into it. But the static level indication on the dipstick might look normal as the torque converter is dry. I kind of assume you drained the torque converter.

You check the fluid level after the transmission has been physically operating and the fluid is hot. So basically you put in a certain needed amount and check the stick after running. Then add a little to top the fluid off. The stick measurement is possibly not a good indicator of the fluid level in your situation in other words.