I had that Hydra-matic in a '59 panel, and 1-4 is "drive" as mentioned. I adjusted the pedal pressure linkage and it helped some, but still banged, thumped, or whatever on either 2-3 or 3-4 shift, I don't remember which. A friend who had the same tranny in a Pontiac said to have the clutch bands replaced, or it will fail....His left him with first and second gears only after stopping at a toll booth! I've heard those trannys are expensive to service these days, but they are unique and cool when rebuilt!
