Overdrive solenoid spring

Frank Miller

Frank Miller

Well-known member
I recently got the kickdown switch working in the 49 but it is not shifting out like it should. The engine stalls but the od does not downshift. Is it possible that the spring is not strong enough to disengage it or that the normally closed contacts are not opening when the normally open ones close? I could not find any specific instructions on adjusting the switch. If I install a stronger spring I need to be careful that it is not too strong to let the solenoid engage the overdrive. Anyone ever experience this?
 
Bring the spring to an old fashion hardware store and look in the spring drawers for one a little stronger. They have hundreds of them,should be something close. Too long and you can always cut one down and reform the cut end to be flat. I get all my springs this way. ken ct.
 
There was a posting here yesterday, "studs or bolts", with an excellant spring chart... Posted by the 5th or 6th guy... Presumably for sale... Check out the chrart, it gives wire size, inicates strength of spring... Sorry that I can't make this easier...
Karl
 
Frank Miller said:
I recently got the kickdown switch working in the 49 but it is not shifting out like it should. The engine stalls but the od does not downshift. Is it possible that the spring is not strong enough to disengage it or that the normally closed contacts are not opening when the normally open ones close? I could not find any specific instructions on adjusting the switch. If I install a stronger spring I need to be careful that it is not too strong to let the solenoid engage the overdrive. Anyone ever experience this?
Click to expand...

I'd double check the wiring before disassembling the solenoid and messing with the spring. The solenoid has two coils, one for throwout and one for holding. The holding coil is not very strong so it could be overwhelmed by a stronger spring.

Make sure the kickdown switch kills the power to the solenoid.
 
That is what I am worried about using a stronger spring. I guess my question is can the n.o. contacts make before the n.c. contacts break? Or has anyone ever heard of a spring failing?
 
Frank,

Personally, I would not mess with the spring in the solenoid. The last thing you want is a solenoid that won't stay engaged because it takes too much energy to overcome the spring. You don't have a spare solenoid that you could check, do you?

You need to make sure that the kickdown switch is both disengaging the solenoid and causing the momentary interruption to the coil. I have an excellent set of troubleshooting steps from V-8 club member Bernie Sawin in Colorado that I will send you if I can find them.

Ken
 
Frank,

I just e-mailed you two troubleshooting documents. This should keep you busy all afternoon.

Ken
 
Kens36 is right about first troubleshooting out the system. The kick down switch kills the coil momentarily until the overdrive solenoid kicks out. There may be a further problem in the kick down switch (shorting to ground somehow) or there is a problem with the points in the overdrive solenoid causing it not to kick out or shorting across the points somehow. The cover is relatively easy to remove but make sure you remove the wire terminal screws if it is the old style since those types screw through an insulator in the cap and on into a terminal inside. Those insulators in the cap on the old ones could cause problems too if they are broken allowing the terminal screw to short to the cap.

Kerby
 
Thanks Kerby. I understand what you are saying. If there is a short there it will only show up when the switch is activated and will not let the circuit open when the solenoid kicks out. I understand relatively well how the whole thing works. Just asking for some experience. With the solenoid de energized I just need to check for continuity from the coil wire terminal of the solenoid to ground and if it is closed I found the problem. Thanks for the help. Leraned something new today.
 
No test drive yet but think I found the problem. The lower contacts make before the upper ones break. I took the switch out and checked conductivity at different positions. So there is a condition when the switch could be out of adjustment it would just ground the coil and stall the car. I adjusted the switch up as much as I could and glued a little tab of sheet metal to the bottom of the gas pedal where it hits the switch. No chance to test drive it yet but I think this will solve the problem. Electrically the rest of the system tests ok.
 
Yeah Ken. It is adjusted all the way up. I just put the sheet metal there so it hits something a little more solid than the rubber pedal.
 
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