My bet would be on the flex disc. Instead of U-joints these cars use a heavy rubber donut that couples the tranny o/p shaft and the driveshaft. Easy to replace with a 15mm and a 17mm wrench and a 8mm hex socket drive.
Over time the bolts are well mated to the rubber donut and the tranny snout is tightly fitted in the donut center so a pry bar may be necessary to pry the flex disc off the tranny and/or driveshaft snouts.
Since there are 3 bolts there will always be one that is up in the tunnel and needs the driveshaft turned to allow access. To do so, carefully jack up the rear at the diff and turn the rear tire (slowly) with the tranny in neutral (chock wheels well in front or have car on 4-stands (GOOD jackstands). When the last nut is accessible lower rear and plae tranny in park and continue job.
DONT get hurt by not taking precautions.
email if you need more specifics.
Oh, the flex disc is about $40 and I have (in driving snow) done it in 20 min (I did get home and have to tighten the bolts again with a breaker bar, but I DID get home
)