Switch pitch question

Discussion in 'The "Juice Box"' started by 455 Powered, Mar 17, 2021.

  1. 455 Powered

    455 Powered Well-Known Member

    Another update. Had some free time today so I headed to the garage to work on the car. Got it jacked up and switched terminals to see if that made any difference. To my surprise it did. I burned up my momentary switch in the new shift knob. Things went downhill from there. Guess it’s coming back out. Car was too hot to check out. I’ll have a look tomorrow
  2. 455 Powered

    455 Powered Well-Known Member

    Finally got to look at the transmission today. When I touch the horizontal spade I hear a slight click. When I touch the other spade it blows a fuse. I’m going to open it up and see if I can find anything.
    TrunkMonkey likes this.
  3. TrunkMonkey

    TrunkMonkey Well-Known Member

    The solenoids are the same with the exception of the shape of the mounting flange.
    (So, having the spade terminal connected to the incorrect solenoid will only trigger the incorrect feature, but will not harm anything.)

    The Top/Horizontal terminal is for the vane control, and the Lower/Vertical terminal is for the kickdown function.

    There is only two things you can have that cause the blown fuses.

    One is the wire inside the transmission to the solenoid has failed insulation and is direct shorting the the case.
    The other is the solenoid itself has shorted.

    Make note of which terminal "clicks" and drop the pan, then see which wire is connected from the back side of the external connector to the solenoid, and post back.

    The one on the bottom next to the valve body is the kickdown detent.

    The other is mounted to the back side of the pump housing.
    You will not be able to access it without pulling the tranny and pulling the pump. (Unlike the ST300 where it is also on the bottom at the valve body)
    Last edited: Jul 24, 2021
  4. 455 Powered

    455 Powered Well-Known Member

    Thanks for the information. I will check it out tomorrow and post what I find. I had the pan off last year and don’t remember any bare wires.
  5. TrunkMonkey

    TrunkMonkey Well-Known Member

    Yeah, the insulation on the inside wires just deteriorates over time. And can be touching the transmission case, or even where the wire enters the solenoid tin cover.

    Especially in transmissions that are pulled and rolled over in the weeds next to the barn with the 1970 Hemi 'cuda convertible 4 speed with 4 miles on it...
    Last edited: Jul 24, 2021
    PGSS likes this.
  6. 455 Powered

    455 Powered Well-Known Member

    Ok. Got pan off and the paddle on the kick down solenoid shorted to the end of the energizing wire. I got that working properly. The converter solenoid is clicking when power is applied. Could the kick down being stuck in the on position keep the converter from switching? Any ideas?

    BRUCE ROE Well-Known Member

    Those functions are unrelated in the trans, but one blowing the fuse
    could prevent both from working. Bruce Roe
  8. 455 Powered

    455 Powered Well-Known Member

    They are both clicking now. Before just the converter solenoid was clicking but not changing the stall.
  9. TrunkMonkey

    TrunkMonkey Well-Known Member

    Seal it up and give it a go and report back.

    If the solenoid is clicking, it should be pulling the needle off the port.

    Not much magic in the solenoid.

    With engine off, key ON, let the car sit for about 30 seconds, then step on the brake pedal and listen for the click, then let off and listen for another click. It is sometimes hard to hear from the seat.

    If it does, then take out on the road and try a start from standstill, put in low, release brake, and drive in low steady about 10 to 15 MPH and watch the tach, it should drop about 500 RPM when the stall goes to normal.

    Then press the brake enough to trigger the switch and see of RPM flares up 500.
  10. 455 Powered

    455 Powered Well-Known Member

    I’m running off a momentary switch. I put it back together and it still didn’t change the idle. I’m getting discouraged. I took the transmission out and I’m not sure what I’m going to do
    TrunkMonkey likes this.
  11. TrunkMonkey

    TrunkMonkey Well-Known Member

    Incoming PM
  12. 455 Powered

    455 Powered Well-Known Member


    BRUCE ROE Well-Known Member

    There has to be a bad part in there, need to keep swapping them until
    it is identified. If that valve is working, do check that the restrictor is
    in place in the case. SWP uses a different input shaft (extra oil
    passage), though they look similar, could it be the wrong one?

    And then there is the question of the converter, though I have never
    had a converter fail this way. Bruce Roe
  14. TrunkMonkey

    TrunkMonkey Well-Known Member

    The pump stator looks OK in the blue, but the red area needs to be checked for depth, and gears need to be removed and look at the pocket for similar wear. That pump may be done.

    The faces can be dressed on a honing table, (removing the stator shaft) and new gears can be milled to fit.
    I know there are thinner gears that were made for resurfaced pumps, but you need to know how much will be have to be removed to restore the surface and if the gear pocket has to be cut, you will need oversized gears.

    (not sure if those are available, but I would think their might be some out there)

    The pump is the life of the transmission, if it's bad, you will have problems.

    You can find remanufactured (new surfaces and gear pocket) pumps for non-switch pitch, but a remanufactured SP pump is unlikely, and you will have to find a shop that can properly do the work.

    If the pump gear pocket is OK, then a good machine shop with a honing table can do the resurface and mill the gears for proper depth clearance.

  15. 455 Powered

    455 Powered Well-Known Member

    Bruce, the restrictor is there and input shaft is correct. TrunkMonkey talked me through this the other night. He also had me verify the solenoid was working correctly and the orifice in the restrictor was open.
  16. 455 Powered

    455 Powered Well-Known Member

    I have a standard 400 pump that I could check to see if the surfaces are in good condition. What is the best method for removing and installing the stator? I have a 20 ton press. There is also a good transmission shop in town
  17. TrunkMonkey

    TrunkMonkey Well-Known Member

    Take it to them and see what they say about the pump halves and if they can do the resurface with the stator shaft in place.

    That would be ideal since it is tight and true as it is. If the haft has to come out, it is pressed out and back in, but you will have to have a proper diameter die to push it out, and it has to be clocked correctly going together as there is an oil circuit hole in the shaft near the base (by the bushing) that aligns with the oil circuit in the pump casting.

    I am not certain if the assembly is done by shrink fitting, or done cold.

    You cannot use non-switch pitch pump halves the pump circuits are very different.

    I used a (new) whet stone 180/240 grit and trans fluid to resurface mine. Took me several days of on and off work (until I got tired of doing figure 8s, but I got it done.)
  18. Jim Weise

    Jim Weise EFI/DIS 482

    While you have the pump out, make sure the orifice plug is in place in the pump mounting surface.

    If it's a poston converter, it has more than likely failed. Just talked to a guy today, sold him my last 12" core.. he had to cut his poston converter off with a sawsall..

  19. 455 Powered

    455 Powered Well-Known Member

    I think it’s time to rethink everything. It might set another year. Thanks for all the help
  20. DaWildcat

    DaWildcat Platinum Level Contributor

    Perhaps not.

    All the advice here is sound, and since you have it apart, you are already very well on your way to diagnosis. The orifice (or lack of) in the trans case behind the pump is an excellent point, easy to check.

    And, at the end of the day if it comes to the converter, any reputable converter rebuilder will lathe it open at the weld for you. That will show all. If you decide to go there, please share photos of the internals right away.

    If it does end up being one of Poston's hack jobs, we can easily spot it. If it is, don't bother rebuilding...move on.

    If not, you have the opportunity to check stator sprag, stator piston moving freely or not, and condition of vanes inside. They should be able to recheck internal clearances and offer torrington bearings instead of phenolic thrust washers.

    If the converter is suspect, that's a great way to go! Check it first, and opening it up is the way to know.

    TrunkMonkey likes this.

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