A buddy of mine that operates a family auto garage told me he's had several issues with ws aftermarket atf that were used with drain, and refill methods. Over time they don't mix well, and cause serious issues where the transmission has to be flushed to correct it. Say's never to use anything else, but the toyota ws atf if doing those 4 qt changes.The Gen2 5 spd AT is a sealed trans. There is a very specific procedure to check the fill level.
You don't need the $$$ Toyota brand ATF at $18/qt. You need to use ATF Type WS. I'll be using Valvoline ATF Type WS for less than $12/qt. I expect <3 qts will be needed for a drain & fill. Full fluid change interval on the Gen2 5 spd AT is 100,000 miles.