most of the time, from what i can see, if the tranny won't move the car then either a) it needs to be pulled apart and checked for broken/burned up parts or b) it isn't installed right check your install and see if everything is tight and plugged in and what not, if it is, then pull the pan, see if you can see anything in the pan that looks like it shouldn't be there (i.e. excessive black powder, metal fragments, ect)

A lot of the cars that i work on, when they quit moving it is one of two things if it has to be rebuilt. its either a) broken parts (planets, bearings, washers, spring retainers, ect) OR you've burned up one or more of your frictions...but then there is the band...My advice would be to just pick it out of the car and pull it apart...better to do it right than to rig it...RIGHT works RIGGED is temporary.