well, i ended up just cutting the drivesahft to get the old one off. (i was pulling it off of a parts car) the drivesahft was rusted...which is why it wouldnt budge. i drained the old diff oil, and filled it with 75w140 mobil 1 synthetic + the diff additive. i regreased the flanges with mobil 1 synthetic grease. turns out the diff is a lsd 4.10, i originally had thought it to be a 3.91. BIG thanks to Regal on his quick and generous help. (pm)