Modern automatic transmissions are filled with babies, voodoo, and black magic. And a lot of them are different from each other, so the arrangement of babes, voodoo, and black magic can be different from one to the other. Failure to have the proper babies : voodoo : black magic ratio will lead to your transmission turning into a rather expensive paperweight.
Don't take it AAMCO, but take it to someone who knows what they are doing. People train for long periods of time on rebuilding transmissions because of their complexity. If the price sounds too cheap, chances are it's just a simple reseal job and won't replace any of the worn hard parts in the transmission itself. Replacing the hard parts is what jacks the price up because it requires special tools, presses, etc.