I took it apart and it appears as though there might be a clutch spring missing (broke off at some point) that pushes the gear out of alignment when the knob is loosened? Everything else looks sound, but there’s no way for the main gear to disengage the spool gear?
From the only viewing angle you provide I can’t see the entire gear train. I highly doubt that any gears move out of alignment.
The free spool function is accomplished with a internal clutch spring which sound be wound around the shaft which the tension knob is located on. Under knob tension, this spring locks the gear to the shaft. This shaft is driven by the first gear to be driven by the motor shaft. Thus when the gear in question (next to your arrow) is locked to the shaft, the gear is locked to the stationary motor (thru the gearing). The spool it also locked to the motor at this time as well.
When you back off the tension knob, the internal clutch spring releases it’s grip on the shaft, allowing the gear(again the one next to your arrow) to free spool on the shaft. This in turn is what allows the cable to free spool.
The internal spring may be broken or it may just be gummed up. You are on the right track, but understand that the gears themselves are not designed to move in and out of alignment to achieve the free spool condition.
NOTE: It might well be that there is no “wound spring” as such, it may be a spring washer or even just one or more flat washers which lock the gear to the shaft.
The winch free spool actually works much the same as the drag on a fishing reel. Tighten the tension knob, the cable moves with the motor. Loosen the tension knob the cable is free to pull out.
The gears on your fishing reel do not move out of alignment either.
