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Hot Rods Turbo 400 question

Discussion in 'The Hokey Ass Message Board' started by mjcat, Feb 2, 2015.

  1. mjcat
    Joined: Feb 27, 2014
    Posts: 85


    Have a question for you guys. My dad has a model A tudor with a turbo 400 in it. Yesterday when he was out for a cruise the trans started to act up. It started out by not wanting to upshift, he had to shift it manually. Once he shifted into 3rd gear or "hi" it would go a little ways and then slip out of hi and into neutral. Any ideas what could have gone bad?
  2. Check the governor and modulator. Any leaks?
  3. You sure it went in to neutral or -
    like neutral and lost forward torque which is slipping ?
    Slipping is not good and if continued will certainly require a rebuild. Don't drive it in the slim chance it's something stupid. Clutches are thin and wear quickly.

    The only things you can do from outside are be sure the shifter is adjusted correctly and not really moving to neutral or resting between detents , check modulator and vac line, check governor. Next is drop the Pan and look for obvious bad shit laying in there.
    A filter change may help. After that it's real transmission work

    Why is there so many turbo 400 problems lately?
    Yours is the 3rd or 4th recently
    caseywheels likes this.
  4. birdman1
    Joined: Dec 6, 2012
    Posts: 1,038


    clutch piston seal leaking

  5. mjcat
    Joined: Feb 27, 2014
    Posts: 85


    Thanks for responses. Ya it's not leaking. Modulator looks brand new, how do I change or check the governor? Where is it located? Gonna drop the pan and see if I see anything in the pan and maybe change filters. Is replacing the clutch piston seal a full rebuild type fix?
  6. saltflats
    Joined: Aug 14, 2007
    Posts: 10,394

    from Missouri

    It would be nice if you could give us some history on the car first.
    The gov is behind a 4 bolt cover on the pass side near the rear tail housing.
  7. Hnstray
    Joined: Aug 23, 2009
    Posts: 11,669

    from Quincy, IL

    My guess would be they are damned OLD and have tons of miles........and are so rugged they often weren't overhauled periodically. :D

  8. potshot
    Joined: Jul 15, 2005
    Posts: 67

    from MT

    First check the fluid level, if it's full and clean looking, check to see if you have vacuum at the modulator.
    If you have good vacuum (at least 15"), but it's still acting up, then pull the governor and inspect the plastic gear.
    Last, drop the pan and see what's in it.
    Joined: Jul 20, 2006
    Posts: 2,423


    I really doubt this is a governor problem, more than likely a clutch pack seal failure. Pull the pan, I am guessng you will find clutch material in the pan. The TH400 is a tough durable transmission, but anything can fail. Because they are so tough, a lot of them are never overhauled before they are put into our rods. Good luck
  10. elba
    Joined: Feb 9, 2013
    Posts: 618


    Your filter is probably very dirty and restricting fluid flow consequently it is dropping out of gear. I have seen it several times.
  11. Good question , seeing they are such "overkill" in a street rod.

    I suspect ,as someone stated , lots of years, miles.
    People flipping cars online too..Many not knowing the history of what they've bought.
  12. 56sedandelivery
    Joined: Nov 21, 2006
    Posts: 6,462


    Shifter adjustment, governor, modulator, wear and tear. Seals hardened with time, especially when not driven a lot. Get it up to temp, throw in a can of Trans-Medic, or something similar, to soften up the seals and see if it shifts better. That's usually only a temporary fix, but it may show you what's going on IF there's not a bunch of trash in the pan. I am Butch/56sedandelivery.
  13. 1930 A
    Joined: Apr 8, 2006
    Posts: 130

    1930 A

    From what you said its probably not the governor gear. If it was stripped the trans wouldn't shift out of 1st gear. Could be bad vacuum though. I've seen where they will shift up through the gears manually but as soon as you let off the gas they downshift and feel like they're in neutral.

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