I had this problem, the bolt through the center of the tranny mount just kept spinning and would not come out, even after hitting it with a BFH. I wound up unbolting the tranny mount from the transmission, and was able to jack up the tailshaft of the trans and get the crossmember out. Then I took a sawzall to the old mount and bolt to get them gone. A new bolt with washer and nut were less than 2 bucks at home depot. Come to think of it, the tranny mount was only $3 and change from rock auto.