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T-85 and Overdrive Oil Change

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  • Transmission / Overdrive: T-85 and Overdrive Oil Change

    I am going to drain the oil on my 56 President Classic, how long it has been in there who knows. I will drain the transmission first, followed by the overdrive unit.
    How do I pump the oil back in? I don't know what to ask my local FLAPS for the item. Is it available on Amazon or Rock Auto? I know it is plastic and has the pump in line with the drive.

    What weight oil should I put in here in the Baked Apple (Tucson AZ)? I have been told 30 weight or 90 gearoil. What is the volume of oil for the transmission and overdrive?

    Thanks in advance

    Bob Miles

  • #2
    Here's one at Advance Auto. They will be near where the gear oil is in the store. Basically it's just a hand pump for transmission lube. Make sure you get the right transmission lube, it's not the same as for the rear axles.

    Click image for larger version

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    Winston-Salem, NC
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    • #3
      You want 90 wt. GL-1 Gear Oil. The Overdrive does not like extreme pressure additives found in more modern gear oils, and the brass synchronizers do not like the modern oils either.
      Napa will have or can get the GL-1. P/N NHF 65201

      Non detergent 30 or 40 wt. motor oil is an acceptable substitute.



      • #4
        I used 40 wt. non-detergent in my T86 overdrive. It shifts much better than with whatever was in it before. I sourced mine from Tractor Supply since none of the auto parts stores had it.
        "In the heart of Arkansas."
        Searcy, Arkansas
        1952 Commander 2 door. Really fine 259.
        1952 2R pickup


        • #5
          Thanks everyone for the help. It rained last night so today we will be having a cooling trend of 90 degrees. I will be off to CarQuest for the pump and we have several other sources for the oil. Up on 4 jacks stands and away we go

          Bob Miles


          • #6
            This is the good stuff. Smoothest shifting, hot or cold. Fill the gear case first, then the OD unit. Click image for larger version

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            • #7

              Did you get this at your local FLAPS or do I need to search for it at a specialty store? Since you have had T-85's for years, I defer to your expert advise. I sure don't want to have to rebuild a good working transmission or overdrive unit. I see the import applications so I was just wondering. What is the capacity for the transmission and overdrive? As I recall, the amount is 5 pints for the transmission.

              Bob Miles