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

T90 To T18 Swap

Discussion in 'Early CJ5 and CJ6 Tech' started by colojeepguy, Aug 5, 2022.

  1. Aug 8, 2022
    Jw60

    Jw60 Airbender and interrupter of the light guard. 2022 Sponsor 2021 Sponsor 2020 Sponsor

    Sedalia MO.
    Joined:
    Apr 8, 2008
    Messages:
    3,081
    If I had a good drawing of the tunnel cover, I could ask my C10 building neighbor with a fab shop to add a part to his offerings.
     
  2. Aug 8, 2022
    Fireball

    Fireball Well-Known Member 2022 Sponsor 2021 Sponsor 2020 Sponsor

    Pullman, WA
    Joined:
    Feb 9, 2018
    Messages:
    4,311
    Somewhere around here I have a 1:1 cardboard template I'd be happy to send you. For the life of me I can't find it (we've done a lot of unpacking and organizing in the last 2 years). I'll dig deeper tonight to see if scare it up.
     
  3. Aug 8, 2022
    colojeepguy

    colojeepguy Colorado Springs

    At the foot of...
    Joined:
    Apr 4, 2010
    Messages:
    6,204
    That would be great (y)
    I haven't given a lot of thought to the tunnel cover yet, still worried about sorting out the mechanics. Seems like copying what the factory did would be simple.
     
  4. Aug 8, 2022
    Fireball

    Fireball Well-Known Member 2022 Sponsor 2021 Sponsor 2020 Sponsor

    Pullman, WA
    Joined:
    Feb 9, 2018
    Messages:
    4,311
    Other things to note from doing this conversion.

    1) Grinding:

    I don't know what adapter you are using, but with the clocking of the Novak adapter and 80's Ford T-18 (with reverse to the rear), I had to do extensive grinding to get the dual lever front cover to fit.

    There was well over a 1/4" of interference. I did a lot of grinding on both the transmission and the dual lever tower:
    [​IMG]

    [​IMG]

    You can just fit a piece of paper through now:
    [​IMG]

    You also need a bunch of grinding for clearance at the one bolt that goes in from the front:
    [​IMG]

    2) OD Shifter.

    With the dual lever front cover, there isn't much room for the OD shifter linkage and it's forced to be somewhat high up. I fabbed a mount to put it in line with the Transmission shifter:
    [​IMG]

    This was my best guess at what would clear and it was totally wrong:
    [​IMG]

    The offset rear hit the floorboards. After about 5 iterations with the transmission in the jeep, the front got dropped lower and the rear ended up above the OD shift rod. The final product looked a lot different:
    [​IMG]



    If I did it again, I would just use the single lever front cover and fab a dual lever mount that bolts to the transmission and incorporates the OD shifter all in one assembly. I think it would be less work.
     
    Last edited: Aug 8, 2022
    melvinm likes this.
  5. Aug 8, 2022
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
    Joined:
    Sep 23, 2002
    Messages:
    12,244
    A simple solution for the bolt that goes through the adapter from the front into the transfer case is to use a reduced-head header bolt. Allows you to use a smaller wrench and stays captured. Just remember to put it through the adapter before installing the adapter. I started doing this somewhere around 20 years ago and it makes life really simple and no grinding needed.
     
    Rich M. and Fireball like this.
  6. Aug 8, 2022
    colojeepguy

    colojeepguy Colorado Springs

    At the foot of...
    Joined:
    Apr 4, 2010
    Messages:
    6,204
    I'm using the stock Jeep adapter, this trans has a D20 on the back of it now.
     
    Fireball likes this.
  7. Aug 8, 2022
    Fireball

    Fireball Well-Known Member 2022 Sponsor 2021 Sponsor 2020 Sponsor

    Pullman, WA
    Joined:
    Feb 9, 2018
    Messages:
    4,311
    Nice solution!
     
  8. Aug 8, 2022
    Rich M.

    Rich M. Shoe salesman 2022 Sponsor

    Maryland
    Joined:
    Mar 23, 2008
    Messages:
    1,736
    The Jeep T18 in mine didn't require any grinding for the twin stick.
     
    Fireball likes this.
  9. Aug 8, 2022
    Fireball

    Fireball Well-Known Member 2022 Sponsor 2021 Sponsor 2020 Sponsor

    Pullman, WA
    Joined:
    Feb 9, 2018
    Messages:
    4,311
    There's another good argument for a Jeep T18 vs a Ford T18 besides already coming with an adapter.
     
  10. Aug 8, 2022
    colojeepguy

    colojeepguy Colorado Springs

    At the foot of...
    Joined:
    Apr 4, 2010
    Messages:
    6,204
    The downside is the input shaft, which is approximately 16 ft long.
     
    ITLKSEZ, Muzikp, m38a1327 and 3 others like this.
  11. Aug 8, 2022
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member 2021 Sponsor 2020 Sponsor

    Bozeman, MT
    Joined:
    Jul 18, 2013
    Messages:
    4,851
    there were jeep T18s with short input shaft from CJs.....albeit more 4:1 than 6:1
     
  12. Aug 8, 2022
    oldtime

    oldtime oldtime

    St. Charles,...
    Joined:
    Aug 14, 2006
    Messages:
    3,254
    Right, get the 1977-1979 Jeep WR T18 if you can find one. The 1979 version has the late type case and shift tower.
    I rather prefer the earlier 1977-1978 shift pattern.
    They have a 17 tooth maindrive gear that measures 7-3/8” stickout or 10” OAL.
    Or you could have the 16 foot long (J truck) maindrive gear shortened. That way you get to use a 1-1/8” clutch disk hub.
     
    Last edited: Aug 8, 2022
  13. Aug 8, 2022
    jpflat2a

    jpflat2a what's that noise?

    Riverside CA
    Joined:
    Jul 30, 2003
    Messages:
    8,410
    Have you confirmed what the actual problem is/was ?
     
  14. Aug 8, 2022
    colojeepguy

    colojeepguy Colorado Springs

    At the foot of...
    Joined:
    Apr 4, 2010
    Messages:
    6,204
    Nope. I'm still assuming clutch, but I haven't got the bellhousing or clutch off yet.
     
  15. Aug 9, 2022
    colojeepguy

    colojeepguy Colorado Springs

    At the foot of...
    Joined:
    Apr 4, 2010
    Messages:
    6,204
    So, in that other thread you referenced these part numbers- is this mated to a stock 225?

    Clutch pressure plate is from a 66 Chevy II LUK 04002 10-1/2" FLAT Diaphram
    Clutch disc is from a 77-79 cj5 1-1/16" 10 spline 10-1/2" Diameter
    Release bearing is National 1697-C this is the super long bearing
    Clutch fork is 66-71 cj5 V6
    Clutch ball stud is the standard GM 1-1/2"
    I am running a cable actuated clutch tied to stock underfloor pedals.
     
  16. Aug 9, 2022
    Norcal69

    Norcal69 Out of the box thinker 2022 Sponsor 2021 Sponsor 2020 Sponsor

    Northern California
    Joined:
    Sep 6, 2014
    Messages:
    2,938
    That is the combination that I have been running and daily driving without issue since the thread.
     
    wheelie, Renegade ll and colojeepguy like this.
  17. Aug 14, 2022
    colojeepguy

    colojeepguy Colorado Springs

    At the foot of...
    Joined:
    Apr 4, 2010
    Messages:
    6,204
    Well we pulled the T18 out of storage this morning, that was a project by itself!
    Ready to start the conversion.
    20220814_100109.jpg
     
    Norcal69, Rich M., Twin2 and 4 others like this.
  18. Aug 14, 2022
    colojeepguy

    colojeepguy Colorado Springs

    At the foot of...
    Joined:
    Apr 4, 2010
    Messages:
    6,204
    Ethan learning how to remove a Warn overdrive.
    20220814_101337.jpg
     
    ITLKSEZ, Muzikp, Norcal69 and 10 others like this.
  19. Aug 15, 2022
    colojeepguy

    colojeepguy Colorado Springs

    At the foot of...
    Joined:
    Apr 4, 2010
    Messages:
    6,204
    My flywheel is nice and shiny after a trip to the machine shop.
    20220815_165543.jpg
     
    dnb5853, Rich M., Twin2 and 4 others like this.
  20. Aug 16, 2022
    colojeepguy

    colojeepguy Colorado Springs

    At the foot of...
    Joined:
    Apr 4, 2010
    Messages:
    6,204
    Well, since I'm going ahead & swapping the trans, I changed the thread title to reflect that.
     
    Glenn, Jw60 and dnb5853 like this.
New Posts