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Technical Slant pan hydro hangs in 2nd

Discussion in 'The Hokey Ass Message Board' started by Groucho, Aug 6, 2020.

  1. 20200806_151514.jpg View attachment 4778288 In my 32 sedan that's probably about 2400#, the trans hangs in 2nd until it's almost floating the valves or I let off the gas. Very annoying! The way it's set up is the linkage going to the trans is pushed by the carb linkage. I bet it's supposed to pull!. Any ideas? . THX
     
    Last edited: Aug 7, 2020
  2. justpassinthru
    Joined: Jul 23, 2010
    Posts: 616

    justpassinthru
    Member

    It's unlikely that you will ever get it to shift right with that setup. I

    Early Hydramatic trans linkage is really somewhat complicated.

    There are basically two stages to it. One stage, for the normal travel of the throttle linkage and a second stage for passing gear.

    The geometry/rate and travel have to match how it was on the original carb/linkage setup.

    There was a thread a few weeks ago where the original linkage setup was adapted to a Holley carb for a Roto Hydramatic (Slim Jim). Although a different model Hydramatic, the trans linkage is quite similar to the Dual Range Hydramatic you have.

    Do a search and you will see what's involved to make it work right. The thread was quite detailed with good photos.

    Bill
     
    ottoman likes this.
  3. Atwater Mike
    Joined: May 31, 2002
    Posts: 11,618

    Atwater Mike
    Member

    Definitely some progressive geometry involved here: @JUSTPASSIN is correct on all counts. I corrected a Dual Range kickdown link problem in the early '60s, Olds w/hydro in a '40 Coupe. Two bellcranks at differing rates and some surplus aircraft parts.
    That was then...
     
  4. 57JoeFoMoPar
    Joined: Sep 14, 2004
    Posts: 6,456

    57JoeFoMoPar
    Member

    You may be referring to the thread I posted. It was actually a Jetaway Hydramatic, not the Roto-Hydramtic, though you're right that they are very similar. I'll link it here.

    https://www.jalopyjournal.com/forum/threads/tech-holley-with-a-jetaway-hydramatic.1199718/

    With only a small adjustment it worked perfectly. One thing I've noticed about the Hydramatic (both the Jetaway and the Slim Jim I had in my 61 Super 88) is that they are incredibly sensitive to TV adjustment. A 1/2 turn adjustment on the linkage might be the difference between your trans shifting properly and not. After I got my adapter plate installed I was getting a bit of a late shift in second. 1 turn on the adjuster, which felt like nothing at all with fine threads, was all it took to get it behave properly.
     
  5. junkyardjeff
    Joined: Jul 23, 2005
    Posts: 8,689

    junkyardjeff
    Member

    I think the linkage is supposed to be pushed down and might be pushing it down too much making the trans think the pedal is to the floor causing the late shift.
     
  6. Ok, update. Looking at the trans someone flipped the throttle pressure lever 180, so all adjustments are now backwards. Now that I've adjusted the right direction it's working pretty good. Adjusted 3 times and I think 1 more will be perfect.
     
    427 sleeper and warbird1 like this.
  7. 57JoeFoMoPar
    Joined: Sep 14, 2004
    Posts: 6,456

    57JoeFoMoPar
    Member

    Great news. It really is a trial and error situation in terms of adjustment. The hydro can be notorious for a hard shift, which is harder on the people in the car than on the trans. Glad to see you're on the right track.
     
    427 sleeper likes this.

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