518 short shifts and no od

If it is a non lock up unit you need the 2 wire connector just behind the manual linkage hooked up for overdrive.
The 1-2 shift is correct at 20 mph at light throttle an 3rd should be about 30 mph or so.
If you let it shift from 1-2 then mash the throttle to the floor it should down shift to 1st gear at low speeds like 25 mph.
If it is shifting 1-2 every time you take off from a stop it is not the governor.
How do you have the overdrive wired up?

yes it is a two pin connector, it short shifts even with 3/4 pedal, the only way it won't is if i hold in first and wot wich would be fine but i hate the way it will shift under light throttle even if i'm in manual low.
i have 12v going to one wire and a toggle switch breaking the ground on the other wire.

how much range should my cable have? when it is set so that it barely comes tight at wot it has some play at idle.
thanks guys for your help here .