1. Registration trouble? Please use the "Contact Us" link at the bottom right corner of the page and your issue will be resolved.
    Dismiss Notice

T86aa Synchronizers

Discussion in 'Early CJ5 and CJ6 Tech' started by B_hester, Jun 7, 2016.

  1. Jun 7, 2016
    B_hester

    B_hester Member

    Joined:
    Dec 23, 2014
    Messages:
    75
    So in my 1966 cj5 my t866 has been having some issues. Ive narrowed it down to the synchros being the issue, and I want to get all the info I can on them before I buy new ones. I found a synchro unit for sale a few days ago but i couldnt find them today. How many synchros are there in this tranny? Just first gear or? Would the 100 dollar synchro unit be all i need and if so does anyone know a good place to buy new ones?
     
  2. Jun 7, 2016
    Pack Rat

    Pack Rat Old Timer

    I live in a...
    Joined:
    Apr 1, 2006
    Messages:
    1,512
    Only 2-3. I might have a new old stock one but you might want to narrow down what your problem is first. What exactly makes you think it needs the synchro?
     
  3. Jun 7, 2016
    timgr

    timgr Eppur si muove. 2020 Sponsor 2019 Sponsor

    Medford Mass USA
    Joined:
    Aug 10, 2003
    Messages:
    21,437
    You mean the blocking rings? There is a synchromesh hub that slides into the blocking ring. One hub, two blocking rings.

    Yes, describe your symptoms. A T-86 is an "advanced" T-90, and it may be cheaper to put all new T-90 gears in the T-86 case, rather than find parts for a T-86.
     
  4. Jun 7, 2016
    B_hester

    B_hester Member

    Joined:
    Dec 23, 2014
    Messages:
    75
    Everytime I shift the gears will grind, as well as it poping out of third every time I let off the gas. Also when I dropped my tranny a year ago I saw that the gold colored ring (which I later realized is part of the synchro unit) looked like its teeth were worn. At time time I didnt really even think anything of it.
     
  5. Jun 7, 2016
    timgr

    timgr Eppur si muove. 2020 Sponsor 2019 Sponsor

    Medford Mass USA
    Joined:
    Aug 10, 2003
    Messages:
    21,437
    The gold-colored ring is the blocking ring, sometimes called a synchro ring. They are a wear item, and when worn the gears will clash when shifting, but they should not affect staying in gear. I expect you are going to have to take the transmission apart and inspect for worn parts, more than just the blocking rings.

    Herm sells a rebuilt "modified" T-86 that is a T-86 case with T-90 gears. If you have a lot of parts to replace, that may be a practical choice. Or you can find a T-90 core transmission and rebuild your T-86 with T-90 gears... there are plenty of new parts for the T-90, not so many for the T-86. T-86 Transmissions | Herm The Overdrive Guy

    There's lots of information about rebuilding the T-90 online, like here The Novak Guide to Rebuilding the Jeep T90 Transmission
    The process for a T-86 is the same, except none of the gears are interchangeable.
     
  6. Jun 22, 2016
    B_hester

    B_hester Member

    Joined:
    Dec 23, 2014
    Messages:
    75
  7. Jun 22, 2016
    timgr

    timgr Eppur si muove. 2020 Sponsor 2019 Sponsor

    Medford Mass USA
    Joined:
    Aug 10, 2003
    Messages:
    21,437
    Unless I could see it, I would worry that part is wrong for the T-86. The T-90 has straight splines on the main shaft, and the T-86 splines spiral.

    This is a T-86

    [​IMG]

    Notice the spiral in the main shaft splines, and the bevel of the sliding gear teeth. Both are straight in a T-90.

    <edit> I dashed this off on my way out the door at work... thinking about it a little more, the synchro hub may exchange between the T-90 and T-86. Everything I've heard/read says you have to use everything from a T-90 or everything from a T-86, except the case and top. If the hub works for either transmission, you can get T-90 parts from oodles of places. If I needed a hub, I'd call Herm and 1) ask if the T-90 hub will work and 2) get the part from him.
     
    Last edited: Jun 22, 2016
  8. Jun 22, 2016
    Unkel Dale

    Unkel Dale delivery on my Jeep from Ft. Campbell, Ky.

    Pittsburgh, Pa.
    Joined:
    Feb 3, 2013
    Messages:
    680
    I have a complete. now spare, COMPLETELY DISSASSEMBLED T 86 IN THE GARAGE, Is it you?
     

Share This Page

New Posts