Hydramatic transmission differences?

I have a Hydramatic that was pulled from a hudson that needs rebuilt. I called around to find out what the cost was, and it’s pretty expensive. There’s only one shop I found that would rebuild it. I just found a Hydramatic transmission that was pulled from a 56 olds for a really great price. Would this work on my 51 pacemaker that I’m getting ready to put a 308 in? Or if there are differences could I change things out from the builder transmission I have?

Comments

  • ChrisPacemakerChrisPacemaker Posts: 9Member
    The transmission I found has been rebuilt already.
  • 54coupe54coupe Posts: 254Member
    I don't know the answer to your specific question. I do know, however, that there were different gear ratios offered in other applications. The Hudson version, (in my opinion) has too large of an rpm drop between second and third gear. There is a Hudson in our family with a Dual Range Hydramatic out of a Lincoln, that has a great gear set in it that doesn't have the big drop, and works really well. Hopefully the Olds unit will be favorable as well. At a minimum, you will need to use the bell housing from the Hudson. The tail shaft may be a different length as well... I know the Lincoln was way longer, and needed to be swapped as well.
  • ChrisPacemakerChrisPacemaker Posts: 9Member
    Cool thank you for the info. I figured it would work, but I was wanting to get some confirmation before I bought it. 
  • 54coupe54coupe Posts: 254Member
    Some models also have a dipstick tube that attaches to the oil pan, instead of checking it through the floorboard
  • GlowplugGlowplug Posts: 1,877Expert Adviser
    If you decide to rebuild your transmission, I recommend Don Chase in Nebraska.  Contact info in the WTN or see the new roster on the H.E.T. club site.  In my early association with Hudsons, Pontiac and Olds trans were the units we sourced when replacing H variants. 
  • tombiatombia Posts: 149Member
    The 56 Olds transmission is completly diff. called a jetaway. they are both just called hydramatic. 
  • GlowplugGlowplug Posts: 1,877Expert Adviser
    The Hydramatic transmissions had many variations.  A list with timing of the naming and designs follows: https://en.m.wikipedia.org/wiki/List_of_GM_transmissions

    The second link is a history of design which brings use and change into perspective.  The Hudson 2-3 is part of the discussion as a general operational problem.   Later specifics changes like Olds Jetaway are also described.  Early GM 50s Hydramatic trans were very much cousins in parts and operation.  Using Olds guts in a Hudson were discussed by Gus Sousa when giving his tech presentations. https://en.m.wikipedia.org/wiki/Hydramatic
  • ChrisPacemakerChrisPacemaker Posts: 9Member
    I appreciate all off the information everyone. I have went back and forth on getting the Hydramatic rebuilt or just using the 3 speed overdrive I have running in the car already. It works well, a automatic would just be nice.
  • super-sixsuper-six Posts: 281Expert Adviser
    The 1956 Oldsmobile automatic transmission is not necessarily a Jetwaway. Both the Jetaway and the Dual-Range were offered that year.

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