since i already had the driveshaft off and tranny out, i thought i'd replace the ujoints.
the rear u-joint was a real PITA. even after multiple days with PB Blaster sprays, i manages to snap the cast iron housing on my 4" Crapsman vise trying to push out the frickin joints.
continued soakings while waiting for the new 5" vise (not craftsman) to arrive definitely seemed to do the trick, as the old was replaced with new on the rear.
when i moved to the front, i got cocky and managed to put the new ujoint in with the grease zerk facing front, eliminating the possibility of ever accessing it in the future.
since i was a pro at this now, removal+reversal+reinstall only took minutes.

remember, if it's not worth doing twice, it's not worth doing.
oh yeah- after my local machine shop charged me $80 to put my new king pin bushings in last year, and $120 to buy and press in a pinion seal, i was going it alone this time.

 

it a little late now but you can rent a u-joint puller that is easer to use than a vice. and less chance of bending the yoke. after i used one. i now own one. get it with the balljoint cups and all that.