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The relay should come in when governor reaches speed -- roughly 17-20 mph and will stay in as long as you are above the governed speed or have not done a kickdown. The solenoid will also stay energized since thru the relay is the only way it gets power. It will stay that way and not go into OD until you momentarily let off the accelerator.

Letting off the accelerator slows the engine but the tires are still turning at speed. That slight momentary speed difference lets parts in the OD shift around and line up parts to unblock the path so the solenoid can fully push the pawl into the sun gear. Once the sun gear is locked you are in OD.

When you press the accelerator all the way to the floor and hit the kick down switch the relay and solenoid will drop out and stay out as long as the accelerator is held all the way down as it might be when passing a car. As soon as you let the accelerator relax a bit from full throttle -- even a tiny amount -- so the kickdown switch closes again, with the car still going above the governor speed the relay will re energize and power the solenoid again to get ready to go into OD.

It will stay that way again and not go back into OD until you momentarily let off the accelerator and repeat the mechanical process.

One possibility on the relay clicking is the rivets connecting the terminals have become oxidized or loose and are making poor contact. That can happen if the terminals are subject to force or if the phenolic material they are mounted to shrinks a bit.

Repro and used relays are available if you need a new one but others have elected to save the $200 or so by taking the old components out of the can and install a modern 40 amp cube type relay in its place. The modern relay fits in the can nicely, is totally hidden and costs around $10.

Ok I think I follow you now Howard but my concern I guess is the kickdown I don't think it's working right because nothing is kicking down when you tromp on the gas pedal shouldn't it automatically kick out the over drive when I do that? Or do I have to manually do that with the on and off the gas pedal? If not could you send another diagram of how to check the kickdown switch thanks for all the help

It should drop out on its own when you tromp the accelerator all the way to floor activating the switch. Part of the switch kills power to the relay letting the solenoid relax and the other part of the switch completes a ground coming from solenoid to short out the ignition for a few sparks. With the ign shorted the engine loses torque letting the spring pull the plunger and pawl out of engagement. Once the solenoid plunger moves out a bit contacts inside the solenoid open the ground so engine fires on all cylinders again and you are out of OD.

Not sure exactly which switch yours has but there should be 4 terminals. If it is the typical rectangular box, to check the switch remove the two wires on the terminals closest to plunger. Those are in the relay power circuit. Use an ohmmeter and with the accelerator relaxed there should be continuity between the two terminals. Have someone push the accelerator all the way down. There should be a small tab on a part of the linkage that hits the plunger and pushes it almost all the way into the switch. The bottom two terminals should lose continuity which would drop out the relay. The upper two terminals are for the cutout circuit and work just the opposite. If you want to check those then the procedure is the same except they should be open when accelerator is relaxed and closed when the plunger is up.

I would also check the travel of accelerator. For some reason there have been a couple of posters lately who have said the switch plunger is not being moved enough or even at all when accelerator is mashed.

Assuming the switch is good, causes for mechanical engagement problems have been varied. One was the little tab that hits the plunger was bent and missing the plunger. The linkage adjustments can be incorrect so the accelerator is not moving far enough before the carb throttle plates are all the way open thus stopping the action. Another possibility is the accelerator pedal is bowed in the middle so the middle of pedal is hitting the carpet and stopping the upper end of pedal from moving the linkage far enough. On the 51-4s there is a bracket on the firewall above the accelerator about even with the head near the left side of engine. That normally has a rubber isolator so it is free to move slightly but is still fairly snug to firewall. If the rubber has deteriorated or fallen out the bracket could be cocking and preventing a full range of motion. A final possibility if the switch has the long threaded neck is perhaps the height of switch is misadjusted and too high for the plunger to activate.