Use a generous supply of WD-40 or other rust buster. If you hsve to use force, make sure you don't damage the transmission tube. Once the old bearing sleeve is off, take emery and clean the shaft where the replacement sleeve will go. Don't overdo it; just get it clean enough that the new sleeve fits into place. It doesn't need to freely spin: it needs a little friction to work properly. I highly recommend you also replace the tub and stem support along with the new bearing. If you do, there is usually enough lubrication on the seal to make it work. Here's the part number for the kit. Part number: AP244279

To get the sleeve bearing off the tranny shaft, use a metal rod or punch, stick it in the tranny groove and pound up on the punch.