i've always been told to do a soaking shot of liquid wrench (overnight) then pulling/wrenching and tapping with a hammer at the same time.

4.2 '87 yj, 263,000 miles, mopar mpi, 33" mud bfg, skyjacker 4", 3.73 gears, arb lockers-f and r., tom wood's 2.07 shaft conversion, tom wood's hd driveshaft, magnaflow/custom exhaust, 4wd bumper/swing-out tire carrier