I read one of the posts and the member said to drop the pan, unhook one of the lines to the cooler, and run truck till fluid stops flowing from line. My question is, does the pump run through the converter and then out to the cooler? I believe that the majority of the fluid is in the converter, right?
what I did on my '96 silverado: droppped pan, removed filter, scrounge around and found plastic pipe exact same dia as tube on filter. inserted 4" piece of pipe into pick-up where filter mounts ( making sure its tight and wont come out). Converted hard plastic pipe to 5' fex tubing and ran into CLEAN 5 gal bucket with 10/12 qts fluid. wired this big plastic tub that I got at wal-mart (approx 3' in dia)up under truck to catch return fluid. I started truck and ran thru ALL gears . Had my bro to watch and ensure I didnt run 5 gal bucket dry. I did this on my fathers lift. Reinstalled pan, filled and check accordingly. I know this sounds kinda shady, but it worked. Probably spent more time than shop would but saved some dough

 

Find Mark Kovalsky's write-up (it's derived from the factory-prescribed procedure) and follow it. It's in the Tech Articles, IIRC.

It's been discussed several times.