I ran a 48 Packard overdrive behind Chevy 261 in my 52 Chevy during high school and college (late 50's - early 60's). It would shift into OD in all 3 gears when a switch was thrown, but I seldom used that capability because the some of the non OD gears closely matched OD ratios and the shifting was tedious. I used the 3rd and 3rd OD most of the time. OD worked well for cruising. I do remember one OD safety hazard was the car would coast when you let off in OD - eliminating engine braking!
