Should I get a newer 727?

Engine, Transmission & Driveline

  1. Joseph James

    Joseph James Well-Known Member

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    1968. Neutral safety switch is single pin. Can’t find any except on eBay for crazy prices. I understand they changed in 1969. Can I just swap valve bodies? Also, I understand reverse light switch is on 3 pin NSS for later models. Mine is missing the switch under steering column and I can not find one.

    I also have no kick down.

    Replace entire transmission?

    Thanks in advance.
     
  2. CBODY67

    CBODY67 Senior Member

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    Don't be so energetic to start changing major assemblie s due to alleged non-availability of smaller items thereof. Especially what I'd consider "bolt-in" items! As far as I know, the two switches will screw into the same sized hole? Maybe only use one terminal rather than all three? Check and compare the factory wiring schematics for any differences in those circuits and such.

    "No kickdown" has nothing to do with the electrical items mentioned. Pure mechanical linkage between the carb and transmission. Please explain the "no kickdown" situation, as to road speeds and such. On the '68 TF, the only kickdown will be at WOT, not part-throttle as the '71+ models will do . . . other than the normal downshifts which occur as the vehicle slows down.

    CBODY67
     
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  3. Joseph James

    Joseph James Well-Known Member

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    I didn’t think the three pin NSS would work on my transmission. Haven’t tried it, though.

    I haven’t driven the car at WOT. I’ll give it a try next time I head to work. I didn’t know the kick down worked that way.
     
  4. CBODY67

    CBODY67 Senior Member

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    One thing about things on eBay that might seem to be "normal replacement parts", or used to be. UNLESS the vendor has it made specifically for him/her, isn't NOS, then it's usually available somewhere else, too, which is where THEY are getting it. Shop around rather than using eBay as the default source. Which is why I will use RockAuto instead, to see what might be at the local auto supply from normal suppliers instead. Might need to look at different model years, but it's still a good research resource.

    Just some thoughts,
    CBODY67
     
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  5. Joseph James

    Joseph James Well-Known Member

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    The only single pin NSS I have found is NOS on eBay. Currently, I don’t think any are listed. I have not seen and reproductions. Rock Auto has the 3 pin version.

    Only one reverse light switch is listed. For a console shifter :(
     
  6. CBODY67

    CBODY67 Senior Member

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    Once the trans has upshifted into 3rd, then applying more pressure to the accel pedal will result in incrementally more acceleration, as would be normal, until WOT is reached. At that time, dependent upon road speed, the trans will automatically downshift into 2nd or 1st. If the road speed is 60mph, then a downshift into second is appropriate. If the road speed is below about 35mph, then a downshift to 1st would be appropriate.

    These upshift/downshift speeds will be listed in the FSM.

    CBODY67
     
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  7. Joseph James

    Joseph James Well-Known Member

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    Btw, this fell off when I was working on brakes last week. I did find new ones.

    35AD9A20-AE6D-403E-92A2-158198E16BEE.jpeg
     
  8. CBODY67

    CBODY67 Senior Member

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    As I have a '67, '66, and '70, I might need to investigate where the extra wires go. Or how the circuits changed for the 3-pin switch.

    CBODY67
     
  9. Davea Lux

    Davea Lux Senior Member FCBO Gold Member

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    One wire on the NSS supplies the ground to operate the starter solenoid, same as on the single pin. The other two wires complete the hot side of the backup light circuit.

    Dave
     
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  10. Davea Lux

    Davea Lux Senior Member FCBO Gold Member

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    Kick down is adjustable. Usually if there is no kick down, the kick down linkage is improperly adjusted. FSM gives details on how to adjust it. Note that it is hard on the transmission if the kick down is poorly adjusted, you should take care of this item asap. Low transmission oil pressure due to a clogged filter can also cause kick down issues. Suggest that you replace the filter and do a band adjustment prior to adjusting the kick down linkage.

    Dave
     
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  11. Davea Lux

    Davea Lux Senior Member FCBO Gold Member

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    If you search "A727 mopar single pin neutral safety switch" there is a used one for $20 that might suit your needs on E-Bay.

    Dave
     
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  12. Davea Lux

    Davea Lux Senior Member FCBO Gold Member

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    Changing valve bodies will not help as the neutral safety switch is threaded into the transmission case, not the valve body. If memory serves me correctly (always questionable) I believe the 3 pin switch has a different size thread base that will not fit the older transmissions, but I could be wrong on that. The column mount backup light switch is probably a junk yard item. Changing to a later 727 can sometime be a major PIA because the tail shaft mounts are usually different, you will need do do your homework on that one. I probably would not replace the current transmission unless it needs to be rebuilt an even then, only as a last resort, because there is always something that does not quite fit right.

    Dave
     
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  13. furious70

    furious70 Active Member

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    While unrelated to the nss, upgrading to a newer valve body with
    partial throttle
    kickdown

    is one of the more satisfying heavy street car projects you can do IMO.
     
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  14. fury fan

    fury fan Senior Member

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    Yes, you will love driving your car so much more with PT kickdown!

    When you travel a route you are familiar with, that has slow-speed turns (neighborhoods, industrial parks, etc) and your brain is used to the heavy thing lugging in 3rd, you'll be amazed to turn that corner and putter away effortlessly when it drops to 2nd.
     
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  15. furious70

    furious70 Active Member

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    Even better I have the kickdown set to down shift on decel into the corner
     
  16. Darter6

    Darter6 Member

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    Just some photos for you.Switched from a single to a 3 prong on my 68.The column switch was broken..Got the parts from Rock Auto, order for a 1970.Don't forget to order the 3 prong plug too. IMG_2627.jpg IMG_2628.jpg Be sure the length matches to work the rooster comb.I believe the length changed in the 73-up years if I remember. Run extension wires from column switch wires thru the fire wall and follow the path of the neutral safety wire to transmission.You can see the brown wire is for the neutral safety center wire.I used red+white for my 2 wire extension to column.Don't matter what color and they hook to the 2 outer wires from the plug.They can hook to any side as they just complete the ground.
    P.S. If you change the valve body to the part throttle kickdown type, order for the year of the valve body. Hope this helps.
     
    Last edited: May 26, 2019
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  17. 65sporty

    65sporty Old Man with a Hat

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    As Darter6 said above I believe there is a difference in the rooster combs on the valve body. I read it in a different thread. If you do decide to go to a part throttle kick down valve body get the switch that matches it.
     
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  18. Gerald Morris

    Gerald Morris Well-Known Member

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    Do NOT change to a more recent transmission over this trifle! Its not worth the trouble. One can easily enough repair the old single wire neutral safety switch, as was done for my '66 Newport 18 months ago. The different spline counts and other little issues (torque converters, drive shaft yokes et cetera...) all make switching 727s from pre 1969 to post quite tedious.
     
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  19. Dan Scully

    Dan Scully Active Member

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  20. Joseph James

    Joseph James Well-Known Member

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