Your 20 year old owners manual indicated ATF, but they had no crystal ball when writing it so they did not know that ATF was going to go through such drastic changes.

MODERN ATF is bad for the seals. If you INSIST on using ATF, find some type A somewhere. The best thing to do is to use power steering fluid from the auto supply just as Mike Tangas suggested.

I have personally had seal failure after using Dexron, and I read in Popular Mechanix about 10 years or so ago about the changing formula of ATF and how it effects power steering systems.

To change it is best to flush the system by disconnecting the return line from the reservoir and laying it in a drain pan, then pour some P/S fluid through the system while an assistant turns the steering wheel back and forth. About 2 quarts will flush it properly. Then reconnect the return line, fill and turn the steering wheel lock to lock several times to bleed. Replace the filter while you're at it. This is the method that is actually a question on the ASE test.

Merry Christmas,