TORQUEFLITE 56-59  helpful tricks


Safety switches.

Note: this topic is for cars with "N" starting push button (57-58 Torqueflite except Plymouth) and 3 pieces valve body .

The wiring of the starter relay uses two safety switches (see schema), the vacuum switch and the neutral safety switch:

1-  After the "starter switch neutral button" ther's a "vacuum switch" mounted on the intake manifold (2 wires: brown to "N" button switch and yellow to starter relay coil). The vacuum switch is closed when ther's no vacuum , so when the engine is not running. If you push "N" you have + 12V at "ign" prong of the starter relay.
As soon as the engine runs, the vacuum switch opens the circuit and the starter relay circuit is open: if you push too far the "N" button while engine running, no dammage to the starter ..  Note that if you can't start the car (starter doesn't turn and solenoid doesn't click) check this "vacuum switch" or test with shorten its two pins.

2- The other side of the primary starter relay coil goes to ground (to complete the circuit) through the "neutral safety switch"  (brown/white wire). This switch looks like a plug at rear of cable housing support (left side of trans.) with one prong. This electrical prong is always connected to a ball (spring loaded) at the other side of the switch.  All these parts are insulated from switch housing and ground.
When the transmission is in "N" position (i say transmission, not cable or button ) ther's an extension of the manual valve lever which contacts the ball so the circuit is grounded. In all other positions ther's nothing which contacts the ball so circuit is open and the starter relay can't close.

If the 2 switches are OK you can't start the car except in N. Even is cable has not proper adjustement the neutral safety switch prevent starting because it is "linked" to trans. and not to cable. Supposing the cable is enough misaligned that "N" button activates "D" or "R" position (the 2 adjacent positions to N at trans.): the lever in trans. will be out of ball of the switch so the electrical circuit will not be close and the starter will not run.

But it's always possible to activate the starter while you're in D or R: i've seen this on 2 cars. On these cars the neutral safety switch was bypassed (don't know why, surely a "professional mechanic" worked on the car..). The "ground" wire (black/white) was grounded with a screw on the frame near trans. But also the cable was misaligned ! So the car could start and went in R (or D) when you hit the "N" button !! You need these 2 conditions to have a driving condition in N: trans. switch bypassed and misaligned cable.



Note: on pics below i've used another transmission without the correct "ball" neutral switch but pics are correct. Click to enlarge
N R D 2 1
"N" position: the lever contacts the ball of the trans. neutral switch so the starter relay circuit is closed to ground In all other positions, the lever is off the ball so the starter relay circuit is opened; you can't start !
"vacuum" safety switch Starter switch ((57-58 only, N/A on Plymouth) starter relay neutral safety switch
  Other pics of the "N" starter switch. Ther's sometime a problem with the bracket which, after extensive use, is bent. In this case the extension lever can't operate the swich which is too far ...  
Check and install the neutral switch.     Beware !  Never  ... bend the lever with a screw driver ..  as writen in one paragraph  w/o removing the valve body and lever from trans  !.

(3 pieces) Valve body as it is on trans. but seen from above

Transmission  with valve body removed (and also a lot of other parts ...). Correct neutral switch.



note: I've not tested my method on car with integral cable housing and "wheel" adjuster (from 59 to 61 Torqueflite) but i think it works also..

If you look at the FSM ther's a clear explanation "how to adjust" but in fact itsn't very easy when you're under the car. First, i copy the FSM explanations (beware, there are some errors in the '57 Chrysler FSM !!):

  • Push in the "R" push button (not "N"  as said the Chrysler manual..)

  • Disconnect oil filler tube and drain approx. 2 quarts of fluid. Loosen cable transmission adjustable mounting bracket screw.

  • remove neutral starter switch. Place the point of a screwdriver through the opening and against neutral starter switch cam (named safety lever  in my text) to maintain reverse (and not neutral as said  ..)  position of manual lever

  • While holding manual lever in reverse position (so you must push on the screwdriver ..) adjust control cable for free play by pushing in until cable stops. Mark position on cable housing. Withdraw control cable to stop and mesasure travel. Push control cable in housing one half of total travel. Then tighten mounting bracket.  etc..

If someone has been succesful with this method, i say "Bravo". When you push through the neutral switch opening, you see nothing and if you are lucky to find the lever and push it the push button at dash pops immediatly. So you must have an aid who rests on "R" button. And how to push, mark and measure an half travel then tighten the screw ?? In the beginning i've tried this method but the cable was often misaligned and the "D" position was between N and D or worst nothing worked ...

I've found another method which ALWAYS works and is very ACCURATE. The only drawback is that you've to remove the oil pan (but it's instructive to look at the inside of the pan....) and have a new oil pan gasket.

Method (see pics below):

  • disconnect battery (in case of ..)

  • Disconnect oil filler tube and drain  fluid. Remove oil pan bolts and oil pan. Loosen cable transmission adjustable mounting bracket screw

  • have someone in the car which push on "N" and keep its finger on it to prevent that the button pops out.

  • Look at the ball of the manual valve lever sector: it must be seated in the 4nd "hole" (from front). Look also at the neutral starter switch cam: it must be exactly at the center of the ball of the neutral switch. Lightly tighten the adjustable mounting bracket screw.

  • Tell to the guy in the car to push the "1" button and look at the sector ball: now the ball must be exactly seated in the first "hole". If not, push or pull a little the cable then re-tighten the bracket screw.

  • Tell to the guy in the car to push the "R" button and look at the sector ball: now the ball must be exactly seated in the last "hole". If not re-adjust.

  • Make another batch of test with 1 and R positions. Then finish with N to verify if the lever is centered on the neutral safety switch . Tighten the adjustable mounting bracket screw.

  • Your cable is now perfectly adjusted. Re-install oil pan, oil etc..

Ball (and trans.) in "N" position another view of N Ball in "1" position misaligned cable: the ball is between 2 positions control cable adapter and lever. '59 (and later) "wheel"  adjustement instructions



  Below are new large pics (april 2008) i made with the transmission upside down ( as in car) and from R to 1 (one "hole" after the other)
the "ball" ! R position N position D position 2 position 1 position


 (new pics, May 07. Reply to Jeff , 58Dodgeregent on the FWDLK forum :

Another view of a correct installation of the control cable adapter. Wrong installation of the cable adapter ... Cable adapter. Beware when re-installing the adpater and the axle .. Correct installation How to set the lever clearance


Note: this topic is for cars with 3 pieces valve body (56 to 59 1/2 Torqueflite).

If you push the wrong button (i.e "R" , Murphy law..) when you're in forward driving, ther's a feature on the trans which prevents to engage the R position. It's the purpose of the reverse blocker valve which prevents to shift in R when you're in D, 2 or 1. The FSM says:
Should the operator engages the reverse button at speed in excess of approx. 10 mph, the manual valve would be moved to N and when the car dropped below 10 mph the operator would again be required to select the proper push button. This implies that you could go in R if you're driving forward at speed below 10 mph ??

The blocker valve is held against manual valve (governor pressure) in forward positions and you can't go in "R" because ther's a shoulder on the manual valve. If you push "R" the manual valve will go in the adjacent position to R which is N. But at low speed (< 10 mph) the governor pressure can't overcome the blocker valve spring which put the valve in "off" position ! 
When you're in "N", ther's no governor pressure, the spring pushs the blocker valve  so the valve returns to "off" position .

On several transmission i've overhauled I've noted that  the blocker valve was stuck in "off" position !!! Beware ! Don't try to test if you haven't check if it works ...

Note: i've removed the cotter pins to put the valve in "safety" position. In normal condition, you can't see the spring... Trying to shift to R ... "off" position
Interesting article about "Letter series transmission" (G. Riehl) . Please read the advises about transmission fluid ..  Courtesy:  Chrysler 300 Club Int.


Change in production : Between the # unit and its serial there's a letter which indicates the "change in production". Here is the listing with the "engeneering change"


actualised 06/09/2003

  Don't forget to look at the "Torqueflite" IML pages:, ther's also some helpful tips (as "reference service guide" for '59 and later cast iron Torqueflite)


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