Info on a slipping trans

Generally when a trans slips when cold and gets better when warmed up the seals are hardened up. That of course means a rebuild. The bad thing about automatic transmissions sitting a long time is the seals harden. Are the ones in your parts cars hardened, I can't answer that but knowing what I know about transmissions and how easy a torqueflite is to rebuild and how much work it is swapping them out I personally always go through them so I know they'll work when installed. The only parts that may cause the job to be more expensive are badly worn hard parts that need replaced. I've rebuilt numerous 350 Turbo's as well as Torqueflite's and the Torqueflite has less parts and is quicker to do