Because 93 was a 4L60 no E. Kickdown cable ... basically a renamed 700R4.
If memory serves me right ....94-97 V8 4L60es are the same except that 94 (and 93 maybe) used one lockup solenoid vs 2 so it doesnt lock fully ... i think. So there would be one more pin in the later harnesses.
95 was special for some electrical reason
Difference with trucks, vs caprice vs fbody is the tq arm mount on the tailshaft and possibly the linkage arm.
Edit .. here:
http://www.impalassforum.com/vBullet.../269586?page=1