For readily available sources of the Chevy pattern 904 check www.car-part.com and look up the 1980-1983 AMC Concord, Spirit, with the 2.5L, AT, or the 1982 DJ5L postal jeep as the search parameters.
For example, I turned up 35 of these 904 transmissions using the 1982 Concord/2.5L/AT as the...