Dual Range Hydro Question

Ol racer
Ol racer Senior Contributor
edited November -1 in HUDSON
I installed a dual range Hydro that had sat inside many yrs into my '46 Truck. I did the obvious, cleaned the filter screen and installed new seals. There was no debris in the pan nor any burnt odor.



The trans shifts fine except it will not shift into 'high' gear restricting speed to about 40mph. I adjusted the 'throttle pressure rod' slowlly in both directions changing only the 1-2-3 shift points, but not 4th.... Does anyone have any in chassis suggestions to try getting 4th gear?

Any suggestions would be appreciated.

Thanks in advance

Comments

  • Clutchguy
    Clutchguy Senior Contributor
    Verify that the shifter is traveling all the way to the 4th.position. This is adjustible. It could be adjusted to only 3rd,gear. Does neutral work properly?. Are you sure it is a dual range?. My mind slips me all the time?. Just rying to help.:)
  • Unknown
    Unknown
    The shape and location of the throttle body pressure arm on the pressure valve pivot affect the pressure applied to the internal valves used to move fluid and therefore cause the transmission to shift in response to the throttle. The throttle body arm is located on a dual range transmission using a tool which establishes the static or neutral point for the arm. If the arm can not be brought into a location where the throttle travel is sufficient to cause all gear shifts there is another tool used to bend the arm. Then the throttle pressure rod is adjusted within the "window of pressure" necessary to make the transmission shift.

    Your ability to make the transmission shift in 1-3 gears leads me to think one or two things maybe causing the problem.

    1. The throttle arm has insufficient travel to create the pressure needed to get the transmission to move the 3-4 shift valve.

    2. The 3-4 valve is stuck or binding due to varnish or other problems. This is a common problem ... back in the day. In those cases where I have run into this problem in the past ... I took my trans man advice ... run it to get it hot and shift it in and out of gears all the while attempting to build the pressure needed to make the valve operate.

    The valve I am speaking of is in the valve body on the side of the transmission. If it does not unstick... the transmission can be left in the car and the valve body serviced. The HUDSON Hydramatic manual for dual range is very clear on disassembly and repair where tear down is needed.

    Good Luck
  • Ol racer
    Ol racer Senior Contributor
    Thanks for the advice,

    It is a dual range Trans and I can feel it click into each 'detent'. R, L, 1, D, and N.

    I will try adjusting the Throttle Rod differently then read the manual on valve body R&R.

    Thanks again
  • Unknown
    Unknown
    Just a long shot, you could try some Lubegard "red" to see if it will loosen up that sticky valve. Its available at Napa or other flaps parts stores. Because the hydramatic uses a screen rather than a filter debris of any sort often finds its way into the valve body, also lack of fluid changes can often leave gummy deposits. Stay away from Trans X it has acetone like make up that make the , lip and other seals swell up. Lou
  • Ol racer
    Ol racer Senior Contributor
    Thanks you for the advice
  • Unknown
    Unknown
    Ol racer are you sure you have a dual range transmission? My shifter indicater has N 4 3 L R on my dual range.
  • mdwhit
    mdwhit Expert Adviser
    dynolou2 wrote:
    Just a long shot, you could try some Lubegard "red" to see if it will loosen up that sticky valve. Its available at Napa or other flaps parts stores. Because the hydramatic uses a screen rather than a filter debris of any sort often finds its way into the valve body, also lack of fluid changes can often leave gummy deposits. Stay away from Trans X it has acetone like make up that make the , lip and other seals swell up. Lou
    Hi, just a comment on Trans X. After letting my 1953 Nash sit for a couple of years, my Hydro 4-speed actually locked up the rear wheels as I backed it out of the garage. It would not go forward or backwards, and the only way I could move it back into the garage was to jack up the rear wheels with a floor jack and roll it in (you know those Nashes of that area...with the enclosed driveshafts!). Any way, I pulled the pan to clean the screen and then I changed the fluid. At that time, I also put in Trans X, because I had heard good things about it...

    The transmission now works fine and actually shifts smoother than it ever did. It used to sort of "slam" into 2nd gear. But now I have a concern about the comments that Trans X has acetone-like chemicals in it. I would hate to damage the seals in the Hydro. Can you tell me more about Lubeguard "red", and can anyone comment on the Trans X? Thanks!
  • [Deleted User]
    [Deleted User]
    Lucas make a good auto tranny additive.
  • Unknown
    Unknown
    After tearing several of the hydramatics down, many have very hard piston seals. This is a byproduct of two things : no transmission cooler and a general lack of maintaince of these units read fluid changes. I did tear one down that had been treated to a quart of Trans-X , yes it did soften the piston seals, but damage to clutch plates had already been done. If these units have been sitting for long periods specially in high humidity or just outside moisture will condense inside it causing rust on internals . I have used Lubegard on all my valve bodies and governors Lou Cote
  • Ol racer
    Ol racer Senior Contributor
    it is a '53 dual range with 3.07 rear. Can only run 40 mph safely tying to get into 4 gear....It did shift couple times but when sat overnight wont shift up. Must have stuck piston in valve body..I hear Lucas makes a good Additive. Not much faith in 'cures in a can' logic but will try some and drive awhile around town before pulling apart....
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