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How Is A T85 Transmission From A T86

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  • Transmission / Overdrive: How Is A T85 Transmission From A T86

    I have a '56 Golden Hawk with a T85 manual transmission, and recently acquired a '60 Lark with a T86 manual transmission. I gather both were Borg Warner products but don't know what the difference is between these two units. Can anybody give me a basic lesson?
    Tom Clarke

  • #2
    Since no one has jumped in yet, and at the risk of over simplifying, there is no noticeable difference from the driver's seat, but the T-85 is just plain bigger and stronger.

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    • #3
      The T-85 direct Std. and Overdrives are a LOT different than the T-86, the FIRST thing easily noticeable is the removable Side Cover with no Top Cover as the Medium Duty T-86 has.

      It is SO Heavy Duty and strong, that it was evolved into the T-10 4 Speed direct.

      These H.D. T-85 Transmissions required a heavier duty O.D. unit, instead of the R-10, BW developed the H.D. R-11 Overdrive Unit for it.

      Trucks use a Lower geared version of the T-85 and T-85 O.D. and most you find today are from Trucks since the car version was only used in '56-'57 289-4V President Classics and short tail '56-'57 Golden Hawks.
      '58 GH's use the The Long Tail version called a T-89.

      I think the Studebaker Packard '56J Trans. version has different (Packard) gearing and the Input shaft IS different than Studebaker's.
      Last edited by StudeRich; 04-16-2019, 02:54 PM.
      StudeRich
      Second Generation Stude Driver,
      Proud '54 Starliner Owner
      SDC Member Since 1967

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      • #4
        The T86 is a medium duty top loading 3-speed or 3-speed with R10 overdrive used in several variations, mostly for V8 cars and 6-cylinder trucks. The main difference is the '57 and earlier cars were short tailshaft fixed yoke and used a square bolt pattern. The '58-66 used the rectangular Ford pattern with the longer tailshaft and slip yoke.

        The T85 is a heavy duty side loading 3-speed or 3-speed with the stronger R11 overdrive. The '56 Golden Hawk used a unique version not found in any other car. The '57-Golden Hawk had a short tailshaft T85. The '58 Golden Hawk/Packard Hawk used another version, long tailshaft slip yoke, as did some later taxi/marshal special order cars. Around '59, when trucks went to the 289", they used a short tailshaft fixed yoke version with different gear ratios, known as the T89. The T85 was used in various GM, Ford, AMC and Mopar high performance cars from '55-'71.

        Chevrolet engineers needed a 4-speed full synchro transmission for the 1957 Corvette racing program, so they worked with Borg-Warner to rework the T85 to become the T10. Chevy had an exclusive on the T10 until Studebaker began using it in 1961. Then, it was used by Ford, Mopar, AMC and others.

        StudeRich said, The Studebaker Packard '56J Trans. version has different (Packard) gearing and Input shaft than Studebaker's.
        Yes, the input shaft is very different, but I thought the gearing is the same as the Studebaker.

        I had thought the '56J was the first S-P to use the Ford bolt pattern. If the '56 President Classic also had a T85, was it also the Ford pattern? IIRC, the '56s using the T86 were still square pattern.

        jack vines
        Last edited by PackardV8; 04-16-2019, 02:50 PM.
        PackardV8

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        • #5
          OK that issue may need further investigation.
          The only reason I said the Gears are different is because since a different Length and Diameter Input Shaft was needed, it stands to reason that the tooth count would be revised to fine tune it to the Higher torque 352 while they were at it, which would mean mating Gears would need to match.

          Anyone got a loose Input Shaft for a '56 AND a '57 GH handy to check, and put this minor issue to bed?
          I don't see it mattering much, since the two are not interchangeable.
          StudeRich
          Second Generation Stude Driver,
          Proud '54 Starliner Owner
          SDC Member Since 1967

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          • #6
            Originally posted by StudeRich View Post
            OK that issue may need further investigation.
            The only reason I said the Gears are different is because since a different Length and Diameter Input Shaft was needed, it stands to reason that the tooth count would be revised to fine tune it to the Higher torque 352 while they were at it, which would mean mating Gears would need to match.

            Anyone got a loose Input Shaft for a '56 AND a '57 GH handy to check, and put this minor issue to bed?
            I don't see it mattering much, since the two are not interchangeable.
            This may be one of those cases where what "stands to reason" doesn't stand up to research or practical experience. The input shafts interchange and the rest of the transmission stays the same. The gear ratios are identical for the Packard and Studebaker car versions.

            jack vines
            Last edited by PackardV8; 04-16-2019, 03:25 PM.
            PackardV8

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            • #7
              I once bought a 56 Patrician that had a T85 in it for a friend in Spokane. He took the drivetrain out, and used the 374 for a Golden Hawk. He also used the input shaft of the T85 to put into a T10 and also installed that in the 56j. I bet it was one fun car!
              Bez Auto Alchemy
              573-318-8948
              http://bezautoalchemy.com


              "Don't believe every internet quote" Abe Lincoln

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              • #8
                I belive the difference in the gears between the truck and passenger car gears were the truck has a straight cut gear and the passenger car has a bevel cut on the gear. Both I do remember were very heavy to lift.

                Bob Miles
                Pacific Southwest Zone Coordinator

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                • #9
                  Originally posted by 6hk71400 View Post
                  I belive the difference in the gears between the truck and passenger car gears were the truck has a straight cut gear and the passenger car has a bevel cut on the gear. Both I do remember were very heavy to lift.

                  Bob Miles
                  Pacific Southwest Zone Coordinator
                  Yes, the T89 truck version has a straight splined shaft and a straight cut low-reverse sliding gear. This makes it easier to downshift from second to the non-synchro first gear. It also makes low and reverse somewhat noisier.

                  Yes, the T85 has a spiral splined shaft and a bevel cut low-reverse sliding gear. This bevel makes it easier to shift quickly from first to second gear. It also makes low and reverse quieter.

                  The gear ratios are very different for the needs of the vehicle.
                  The car ratios are 2.49, 1.59, 1.00. The closer ratios keep the engine RPM up from shift to shift.
                  The truck ratios are 3.17, 1.75, 1.00 The lower first and second gears multiply the torque to pull a load off from a stop.

                  jack vines
                  Last edited by PackardV8; 04-17-2019, 10:50 AM.
                  PackardV8

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                  • #10
                    Tom another major difference you will find between a 1960 T-86 and a 1956 GH Trans. is that the T-86 uses a slip Yoke one piece driveshaft.

                    The T-85 you have being a '56, has a Fixed, bolted Yoke output Flange that uses a TWO Piece Driveshaft.
                    Last edited by StudeRich; 04-18-2019, 09:41 PM.
                    StudeRich
                    Second Generation Stude Driver,
                    Proud '54 Starliner Owner
                    SDC Member Since 1967

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                    • #11
                      Thank all of you for the information. What a great place this Forum is.

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