'73 with TH400 - won't engage in gear. STUCK IN PARK!

Discussion in 'Troubleshooting & Diagnosis' started by Cptmoney, Aug 20, 2019.

  1. Cptmoney

    Cptmoney Veteran Member

    Messages:
    270
    Likes Received:
    2
    Joined:
    Jun 11, 2012
    Location:
    Rural Western Slope, CO
    My '73 has a TH400 with a console B&M ratchet shifter. Normally works perfectly....but lately, she's been acting up a bit.

    Occasionally I'll reach down to put her in gear - and nothing. Stuck right in park. It's been a relatively minor problem, as normally I putz with it long enough to get her in motion and down the road we go. That is, until this morning. Thought I'd drive her to work - and she ain't budging. PARK - and nothing more! Haha! She sounds great idling in the garage - but I get way more enjoyment from actually DRIVING her around! Hahaha.

    So - I can slightly pull back the rubber shift boot to take a peek in at the linkage, and things look just fine under there. The reverse lock-out wingnut pulls up just fine, and I can see the shift plate sliding up and down just fine as well....but the actual gear shift won't budge.

    It's got me debating if it's an electrical switch that won't allow the tranny to shift into gear or if it's an actual mechanical linkage failure.

    Where do I begin with this one? This is new to me. Not sure where to start. I need your wisdom! Teach me, oh wise tranny gods! Where would you start? I'll snap a few pics this afternoon; I was in a hurry to get to work this morning so I left her as she is.

    I've longed to switch out this ratchet shifter for the horseshoe/staple shifter....perhaps this is the time, yeah? Might end up having her spread out on the garage floor before this one is all wrapped up.

    Tell me where'd you begin...
     
  2. budro6968

    budro6968 Veteran Member

    Messages:
    3,098
    Likes Received:
    482
    Joined:
    Apr 2, 2016
    Location:
    Jax Florida
    I remember a post by Twisted that mentioned The cable had melted the casing B/C of a ground issue? Meaning lack of good ground from engine to chassis caused the shift cable to become a ground. Melts then gets stuck. ?
     
    Cptmoney likes this.
  3. Cptmoney

    Cptmoney Veteran Member

    Messages:
    270
    Likes Received:
    2
    Joined:
    Jun 11, 2012
    Location:
    Rural Western Slope, CO
    Wondering if I can find a wiring diagram online? I have a service manual at the house....but I'm not at home. Still thinking about it....trying to make a plan on how to attack things once I'm home.
     
  4. Cptmoney

    Cptmoney Veteran Member

    Messages:
    270
    Likes Received:
    2
    Joined:
    Jun 11, 2012
    Location:
    Rural Western Slope, CO
    Where are the electrical components to this puzzle? Can I get at them from under the shift boot? Is that where I should start?
     
  5. Twisted_Metal

    Twisted_Metal Administrator Staff Member Lifetime Gold Member

    Messages:
    26,818
    Likes Received:
    875
    Joined:
    Feb 26, 2004
    Location:
    Bloomington, MN
    Th400 has no wiring for shifting. It’s mechanical.
    Only the neutral safety switch and reverse lights have anything to do with that transmission and those are at the shifter or column.
     
  6. Cptmoney

    Cptmoney Veteran Member

    Messages:
    270
    Likes Received:
    2
    Joined:
    Jun 11, 2012
    Location:
    Rural Western Slope, CO
    Does that neutral safety switch/reverse switch have any capacity to keep it from shifting out of park?

    Can it keep the tranny from engaging? Or is purely mechanical?
     
  7. mallard

    mallard Veteran Member

    Messages:
    442
    Likes Received:
    75
    Joined:
    Oct 3, 2013
    Location:
    SK, Canada
    too bad you can't take pictures or a video of this as I can't get my head around what's happening here. Is there a cable slipped out of place? (it's been 40+ years since I've monkeyed with a turbo 400)
     
  8. budro6968

    budro6968 Veteran Member

    Messages:
    3,098
    Likes Received:
    482
    Joined:
    Apr 2, 2016
    Location:
    Jax Florida
    Is your shifter all linkage type? I was thinking of the stock type T-350 floor shift. It had a cable. Not familiar with the B&M shifter.
     
  9. PBZ28

    PBZ28 Member

    Messages:
    30
    Likes Received:
    6
    Joined:
    Nov 3, 2017
    Cable goes from shifter to the linkage arm on the side of the trans driver side. Can you manually shift from under the car? Possibly the cable is loose?
     
  10. Cptmoney

    Cptmoney Veteran Member

    Messages:
    270
    Likes Received:
    2
    Joined:
    Jun 11, 2012
    Location:
    Rural Western Slope, CO
    I'll pop off the boot and take some detailed pics this eve if I can sneak out to the garage for a bit...

    If there's not an electrical switch that is capable of impeding the shifter from moving out of park, then it's got to be a minor mechanical adjustment that needs tweaked. It normally works just as smooth as butter, but it has done this before. Normally a little working it back and forth kicks her to life and away we go. Not this time, however.

    I'm just wondering if the shift lever (that T-handled puller) might need adjusted so that it pulls the lock plate up just a TEEEEENY bit more.

    That's my best guess for what's going on....without looking into it further. I'll snap some pics and post up some video of what I'm seeing. Can't be anything too crazy (famous last words!).
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.