Pan will come off without removing the cross member. Get a can of Brake Kleen and clean up the exterior of the transmission as best you can before removing the pan. If it is just a pan gasket, replacing it and the filter should fix the leak. Note that these transmissions sometimes also leak fro the shift assembly and from the Input shaft for the torque convertor. The o-ring around the front pump assembly sometimes will also leak. Check the pan for obvious dents or other damage. A lot of these leaked from over tightening the pan bolts. This dimples the area around the bolts to where the gasket does mate properly to the transmission case.
Dave