700R4 wiring question

82 half ton 305 4bbl with 700R4 tranny. this transmission has a 4 pin electrical connector, which only uses 3 wires. i have a new plug end for the harness, but i need something that tells me which wire went where. the new connector ($43!!!) comes with 3 wires in it, but they are all white. the original connector disintegrated when i pulled it out, i didn't sweat it then (how hard could it be to figure out... famous last words!) but now, 6 weeks later, i can't come up with any info on it. can anyone help me out with this? thanks zz03