Car turns over (starts) only in N, not Park

I've lived with it, but I know this isn't "correct" in terms of standard 727 functionality. Suggestions, appreciated! Thx

Time to adjust the NSS?

Linkage/cable slightly out of adjustment is where I'd start.

Check for worn/missing plastic bushings in the shift linkage.

Bad neutral safety switch?

This is probably the case. As a side note, I remember my uncle always had Fords as I was growing up in the 60's. It was standard procedure to sit behind the wheel, reach over and pull up on the shifter with your left hand, and turn the key with the right.

Bad neutral safety switch.

Shift linkage adjustment. Park is touchier than neutral.

The linkage can easily be verified by disconnecting it and putting the trans lever in Park. If it magically cranks look at the bushings / linkage adjustment. If it doesn't you may have a mismatched NSS or broken rooster comb

That failure tree has several branches. Could be a bad neutral start switch, missing switch, wiring failure, internal failure inside the transmission, etc.

A visual check is the first thing. See if the wiring is hooked up, is the switch installed, etc. You can check the switch for operation with a voltmeter. If the switch isn't working it could be a bad switch or it could be a busted rooster comb. Might need to pull the pan off the transmission if the string of clues leads you there.

If it starts in Neutral, the wiring and switch would have to be OK

That’s usually the case.

Linkage has new bushings and has been adjusted for clean engagement from P to 1... thinking it's the NSS now. Thx

all the NSS does is complete the ground circuit to the starter relay, allowing the relay to energize the starter circuit.
if it starts in neutral but not in park, the switch is good.
that leaves only the linkage adjustment or the rooster comb as problem areas to address.
the NSS may need to be tightened a little more, or the wiring inspected to be sure the shift linkage is not inadvertently "moving" the plug a little. that tidbit cost me more than a few hairs to be lost before discovering that.

Yes, the pic below shows the contact points that ground the switch, Park is the top arrow and Neutral is the bottom arrow. If it starts in Neutral but not Park, the linkage is preventing the roostercomb from traveling far enough to make contact.

With what he and others are saying

The switch doesn't know or care what position the shifter is in only that the contact point is depressed or touching the rooster comb to ground the signal wire. There are different rooster combs as well.
tightening the switch as MOPARX suggested and if possible may do the trick. The attached pic is a generic 727 valve Body but shows the two points that ground / depress the contact.
Second pic is of a 3 pin NSS with the center pin being the contact point.

Disconnect the linkage at the trans and manually put the trans lever in park and see if it starts. Real easy check.

You treed me with the post & pic John 🍻

Suggested that earlier but🙄?????

The NSS doesn't have different positions for P and N. It is simply an on/off switch that the rooster comb inside the trans actuates.

It's been so long since the issue first popped up that I had forgotten that the problem started after switching to my T/A valve body

It's not the linkage

Maybe the NSS can be screwed in a little farther, but I don't recall it being loose when I was hooking everything up

So the comments re "something" about the rooster comb make sense... what ever the fix is

Have you actually verified that by doing as suggested and disconnecting the linkage then moving the shift lever full back? You will not know for sure until you do this.

While the linkage is disconnected, move the lever through the gears and make sure there is a firm detent at each gear, no slop when it's in a detent. There are rare cases where the shift shaft that is swedged into the roostercomb can come loose and cause excessive play.

Is the NSS original or a replacement. The reason I ask is I bought a NAPA nss switch and it failed like 6 months later. The little pin on the end has gotten damaged somehow. I installed a NOS switch and never had any more issues with it. The NAPA one was made in China. I probably have another one around here .

if the switch works in Neutral it pretty much eliminates the switch.

So for the bazillionth time it has to be either Linkage or the rooster comb itself for whatever reason is not touching the pin.

That's a possibility as I have seen more than one loosen up myself.
A real simple way to diagnose this is to drop the flippin pan and visually see what the problem is. OP just stated the problem started after changing the Valve body 🙄🧩🍻[u][/u]

Yes, this is exactly what I did and why I'm confident in saying it's not the linkage. I spent at least an hour going back and forth between the shifter, the linkage and the lever on the trans adjusting everything to ensure there is clean engagement with each gear and no binding in the mechanism. It wasn't that way to start (felt "tight" at either one end of the range or the other), but the last tweaks left it with good freedom of movement from P to 1.

If there's something going on w/ the rooster comb, I don't know at this time. It will be one of the next things I look into when I crawl back under the car.

Next time use a Volt meter or test light with one end hooked to battery voltage and the other to the middle pin on the switch. If the light turns on or you show V in Park your NSS is working. All it does is provide a ground to energize the starter relay. Your problem would then be the wire between the two

TJP - Thanks for the trouble-shooting guidance

keep us posted

Since you state that the problem started with a VB change, it's possible that the VB maker installed a roostercomb with the incorrect stop plate. The stop plate is cover plate for some of the valves, besides being a cover it provides a stop for the ear on one side of the roostercomb. (area of plate in orange) The pic below shows the two different styles of roostercomb and the stop plate that is correct for each one. If the plate on the right is installed with the roostercomb on the left, it could prevent the roostercomb from traveling all the way to the Park position.

John, could you put all your posts of TF issues in a book or on a thumb drive 🤪. Actually I just wanted to thank you for all you contributions to helping others this site 🍻

Now this post, fellow Mopar people, is what tech help forums are all about. So glad we have experience and knowledge like this that John is willing to take the time to pass along.

i have learned a lot from mr. K over the years, and i hope he continues to provide more in the future.

Indeed!!

Group hug!!!

Is it fixed? If so what fixed it?

The easiest way to determine if the roostercomb is the problem is to remove the NSS (might lose some fluid) and see if you can see (you'll probably need a mirror) the metal contact centered in the hole with the shifter in Park.

John,
On the plates and coms pictured in post # #3188462 is there a way identify which of the two separate combinations is correct for a given year? Out of all the TF's I swapped over the years I nenver ran into the iissue, granted most were part throttle kickdown units but it got me to wondering is that is when the change took place.

I'd have to go to the parts book to be sure but, IIRC, the one on the left is late '68 through '70 one on the right is '71-on.

Mine is 50/50 on working in P but it always works in N. Usually you can rock the car and the pawl will fall in a little more and it will work in P. It is always firmly in park but unless the car rocks back or forward it usually doesn't engage enough for the NS to work. It really only bothers me when I use my bump button when I run the valves. I usually have to rock it back and forth a little for it to go all the way into park.

that would drive me nuts but that's me. On your "Bump Button" or remote starter switch, if you jumper between terminals B and S it will bypass the NSS
If you don't have a RSS they're cheap ad handy when running valves. the following is one example

RSS LINKY

you don't have to jump those terminals.
all that is needed is to wire the G terminal to the mounting bolt, completing the ground circuit. [a spade connector, short piece of wire, and a ring connector terminal]
however, doing that allows the car to start in any gear, so BE VERY CAREFUL if you do this !


edit : the above i posted is used to bypass the NSS using the key to start the car. using a bump switch to run the valves requires hooking up the switch as the picture indicates.
sorry if i caused any confusion !

URR Butt crack was showing on that one 🤣🤣🤣🍻

BTW jumping the terminals will make the car move if in gear with a Standard trans. But it usually doesn't take long for one to figure that out. Especially if the front of the car is on jacks stand's or such

i have found the "cat" will move pretty quick, or get ground up into a ball of fur and guts if it's resting on the engine and the "car" starts, even if it is on jack stands...............

I have a emoji for you but i don't need a vacation 🤣🍻

does that mean i'm "number one" ?

Certainly does right in the middle 🤣

Haven't crawled back under it, yet. Another member just sold me an NOS NSS, so I have a spare should that turn out to be the issue.

just by chance, Do you have Ultra High Compression Screen Top Pistons ? they can cause this condition when carboned up

I got rid of all the chrysler engine wiring. I use a ford style solenoid that is in the trunk. I got it from a Jeep CJ with an automatic so it works with the ground style NSS.