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Technical Ford overdrive question

Discussion in 'The Hokey Ass Message Board' started by Reman, Feb 13, 2020.

  1. Reman
    Joined: Jul 8, 2010
    Posts: 304

    Reman
    Member
    from Florida

    Hello everyone..........Can any of you Ford guru's answer this one......Is the 3 spd od trans in a 57 Tbird the same as any other 57 era Ford od? If it is Tbird specific, what are the unique features? Thanks
     
  2. I dont know but I have one out of a 50 ford.

    Sent from my SM-A102U using Tapatalk
     
  3. 4dsrus
    Joined: Feb 23, 2007
    Posts: 16

    4dsrus
    Member

    Most of the 312 birds and Ford's have the T85 Borg Warner overdrive. The '57 Ford car T85 has a long tailshaft. Not sure on a bird. The T85 has a curved bottom side plate and is much like a T10 Borg Warner4 speed. The 292 and 6 cylinder cars have a square side plate transmission and is much weaker than the T85. Not sure of the tailshaft length and cross member mount on a third.
     
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  4. miker98038
    Joined: Jan 24, 2011
    Posts: 424

    miker98038
    ALLIANCE MEMBER

    All 312's came with the T-85, with or without o/d. Most 292's used the T-86. The o/d is different, R-11 on the 85, R-10 on the 86.

    The T-85 has curved side cover as stated above. Good, tough trans and o/d, good behind a pretty stout FE until the 4 speed came out.

    I don't remember if the tail shaft length is the same, but IIRC the mount position is.

    So, if that 57 came with a 312, it should be a T-85. Most did, but after all these years, who knows what's there? Check the side plate.
     
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  5. enigma57
    Joined: Apr 12, 2007
    Posts: 235

    enigma57
    Member

    As noted by posters above, the T-85 3-speed has a 9-bolt side cover with a curved bottom like the T-10 4-speed which was developed from the T-85. The T-85 is a heavy duty transmission and has the stronger R-11 OD unit with 4 planetary gears. T-birds had the short tail housing. There is a guy from Lakeland, Florida selling a couple of them on e-Bay just now (1 supposed to be in good shape, the other for parts) and you can check out the photos to verify that yours is indeed a T-bird transmission......

    [​IMG]

    [​IMG]

    Note: From casting date the parts transmission in photo below appears to have a later year T-85 side cover (these had redesigned seals where the shift arm shafts exit the side cover)......

    [​IMG]

    [​IMG]

    Disclaimer: I don't know the guy selling the transmissions. Just pulled up the photos to post for you here.

    https://www.ebay.com/itm/TWO-1955-5...502054?hash=item1ce3d57766:g:IwUAAOSwb~xeRFMb

    Also...... When filling (or refilling) a T-85 OD transmission, manual says to fill gear box and OD unit separately, filling OD unit first. Then after a while, double check gear oil level and top off one or both if necessary priour to driving vehicle.

    Hope this helps,

    Harry
     
    Last edited: Feb 14, 2020
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  6. deucemac
    Joined: Aug 31, 2008
    Posts: 1,015

    deucemac
    Member

    Avoid the T-86 At all costs! It has a top cover and is marginal at best. Ford used lots of them. The discription of the T-85 is accurate. That same case was the basis for the T-10, four speed with narrow gear to fit the same csde.
     
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  7. enigma57
    Joined: Apr 12, 2007
    Posts: 235

    enigma57
    Member

    Roger that! The T-86 is a light duty transmission and not nearly as strong as the T-85. Here are some photos of a T-86. Note top cover (no side cover) and light duty R-10 overdrive unit having 3 planetary gears rather than 4......

    [​IMG]

    [​IMG]

    Best regards,

    Harry
     
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  8. Reman
    Joined: Jul 8, 2010
    Posts: 304

    Reman
    Member
    from Florida

    Thanks for all the info guys. Some I already knew and some new to me. My reason for the original question was trying to determine the origin of a T-85 that I have. We removed it from a friends 57 Tbird around 1970. It was behind a FE motor, supposedly a 406. It has been stored since then. I have garnered from this info that the Tbird would have had a short tail housing. Mine has a long tailhousing. Additionally, I have found what I believe to be a date code on it, and it begins with C O, which I take as C meaning 60's and O meaning 1960. Does this sound right to you guys? If so, that means it definately did not come in a 57 anything. Is there anything else that may tell more precisely what it did come from? Not terribly importantly though. I thought if I could verify it as Tbird, it might be worth a pretty penny to Bird restorers. Thanks for all the input and the shared wisdom. Ron
     
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  9. Boneyard51
    Joined: Dec 10, 2017
    Posts: 3,376

    Boneyard51
    Member

    I have a T-86 transmission in a 1960 Ford van that I pulled from a 1957 Ford. While I understand the 200 cubic inch six can’t put a lot of stress on this transmission, I saw a friend of mine put one through pure Hell with a V-8 in a 1957 Ford, with no trouble. Even in overdrive.
    That transmission developed later into the four speed toploader , a very strong transmission.
    But!!! Here the thing with overdrives, they are designed to be used only in with the main box in high gear for high way driving, therefore reducing the torque put on the overdrive gears. Used that way they will last for ever! People shift into over drive in first and second, that puts too much torque on the planetary gears! Most OEMs set them up so you can’t shift into overdrive below 30 or so mph. Well back in the day of overdrives, most folks were in high gear by 30 mph! With a transmission that has a 3 to 1 low gear, you can put three times the force on the planetary gears in low gear vs high gear.










    Bones
     
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  10. Beanscoot
    Joined: May 14, 2008
    Posts: 1,215

    Beanscoot
    Member

    "With a transmission that has a 3 to 1 low gear, you can put three times the force on the planetary gears in low gear vs high gear."

    Very good point.
     
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  11. Reman
    Joined: Jul 8, 2010
    Posts: 304

    Reman
    Member
    from Florida

    I had never really thought about the torque to the planetaries, but it makes sense. I remember many times shifting into od in 2nd gear, then shifting into 3rd. But I also think that I never did break one. I had several T 85's with od, but don't think I ever ran a T86.
     
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  12. miker98038
    Joined: Jan 24, 2011
    Posts: 424

    miker98038
    ALLIANCE MEMBER

    The old Laycock de Normanville o/d's on foreign cars were set up that way. Small engines, 2, 3, or 4, but bigger engines like the 3000 Healys's only in 4th. Kept the torque load down to the o/d gears. T-85's and R 11's were pretty bullet proof. Even the long tail shaft ones (especially for an FE) should be worth something to a restoration guy, a lot of them were replaced by 4 speeds. The Tbird guys might also be interested. Failures were normally in the main case or o/d, not many 312's broke the tail shaft housing or output shaft.

    The T86/R10 was much lighter, but they went millions of miles in thousands of cars and light truck. Just didn't take the abuse of guys like us.
     
    Last edited: Feb 20, 2020 at 9:28 PM
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