What can you do to stop transmission shudder for a 94 crown victoria?

Try dropping and cleaning the pan, changing the transmission filter, and refilling with Mercon V ATF. I use Mobil 1 Multi-Vehicle Synthetic ATF and Amsoil Universal Synthetic ATF in my 2000 Ford Taurus. It makes a huge difference in shifting and performance over regular Mercon V, which is a synthetic blend. Your car probably calls for just Mercon, which is no longer going to be made after July 2007. Ford recommends you use Mercon V, if you previously used Mercon. Mercon V was developed to get rid of shudder problems on Ford transmissions.