You have it right about what needs to be replaced along with the B2 piston BUT you 1. Need to see the car and decide if you really want it (that sounds pretty cheap) 2. Recognize that you must be EXTREMELY CAREFUL about keeping the inside of the trans from getting contamination in it. How far away is it? If it were me and the car ran I would have a buddy go with me and drive it home. If you need to tow it a long distance you should be disconnecting the driveshaft anyway. You don't know what you are going to run into trying to fix things far away from home. Believe me, I've done it many times (mostly when I was much younger) - wouldn't recommend it now. Removing that sleeve is NOT necessarily easy with the trans in car but it can be done. I made a tool to do it but doing that properly far from home is more adventure than driving/towing home IMHO.