i came across a '55 station wagon and a '56 sedan a few weeks ago that had original od units; t-bar pulls. and looking in my '68 manual, it gives breakdown/repair steps but not operational info. knowing that they had solenoids, i thought that's how they're turned on and off, but when i saw the mechanical lever on the vehicles and in the manual, i'm not following the use of both. my old jeep's saturn od was strictly mechanical. ?