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GL-1 90 gear oil ‘50 champion

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  • Transmission / Overdrive: GL-1 90 gear oil ‘50 champion

    I know the manual transmission uses a non-hypoid gear oil, but should it contain friction modifiers? Or is this something that is also only applicable to hypoid gears?
    Last edited by Flthdchamp; 04-12-2021, 08:31 AM.

  • #2
    I don't use anything but GL-1. It seems to work find as is. I would presume that your 50 Champion has survived on a steady diet of it for seventy years. The time to experiment is when you have a problem. If you don't have a problem why take the chance.


    • #3
      Yep. NAPA #65-201 for a one-gallon jug. BP
      We've got to quit saying, "How stupid can you be?" Too many people are taking it as a challenge.

      Ayn Rand:
      "You can avoid reality, but you cannot avoid the consequences of avoiding reality."

      G. K. Chesterton: This triangle of truisms, of father, mother, and child, cannot be destroyed; it can only destroy those civilizations which disregard it.


      • #4
        Thx guys, the previous owner was running SAE 40 but I’d rather run GL-1. I’ve only owned the vehicle for a few months. The transmission has no issues but the previous owner also put very few miles on it. I found a GL-1 with no extreme pressure additives but it also listed no friction modifiers. I wasn’t sure if that mattered.
        Here is the product link:

        looks ok to me but wanted a second opinion.
        Last edited by Flthdchamp; 04-14-2021, 03:35 AM.


        • #5
          The Two "Terms" are describing the Same properties. That more "Local" PSC Brand should be fine.
          Second Generation Stude Driver,
          Proud '54 Starliner Owner


          • #6
            Thanks for checking, I agree


            • #7
              And I hadn't known before I joined the SDC and this had become a topic that SAE 40 engine oil is in the same viscosity range as SAE85W90 gear oil.

              Yes, the key for the OD (if equipped) is not having hypoid additives that 1) attack yellow metals or 2) lower friction in the OD components to the point of poor engagement. Some friction is required in the rollers/ramps/sungear.