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 16, 2022
    colojeepguy

    colojeepguy Colorado Springs

    At the foot of...
    Joined:
    Apr 4, 2010
    Messages:
    7,275
    Yeah, and it looks perfect :confused:
    But at this point I'm replacing everything between the flywheel and the driveshaft so it doesn't really matter.
     
    dnb71R2 likes this.
  2. Aug 16, 2022
    Jw60

    Jw60 Dropping towbars 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Trails end,...
    Joined:
    Apr 8, 2008
    Messages:
    5,023
    Don't forget to upgrade the stay cable.
    :beer:
     
    dnb71R2 likes this.
  3. Aug 16, 2022
    Steve's 70-5

    Steve's 70-5 Active Member

    Louisville, Ky
    Joined:
    Nov 12, 2009
    Messages:
    1,386
    Had a clutch in a chevy truck not shifting right. Clutch was good but clutch fork was wore.
     
  4. Aug 16, 2022
    colojeepguy

    colojeepguy Colorado Springs

    At the foot of...
    Joined:
    Apr 4, 2010
    Messages:
    7,275
    Doesn't have one
     
  5. Aug 16, 2022
    colojeepguy

    colojeepguy Colorado Springs

    At the foot of...
    Joined:
    Apr 4, 2010
    Messages:
    7,275
    It's a 70 with cable clutch, and it works as it should.
     
    dnb71R2 likes this.
  6. Aug 16, 2022
    Muzikp

    Muzikp Active Member

    Sacramento Ca.
    Joined:
    Sep 27, 2016
    Messages:
    1,450
    Should have changed the title to "Trouble 90 to Terrific T18 swap" :D
     
  7. Aug 17, 2022
    Renegade ll

    Renegade ll Member

    Thayne Wyoming
    Joined:
    Feb 17, 2013
    Messages:
    788
    Hey Doug we're with you every step of way.
     
    colojeepguy likes this.
  8. Aug 17, 2022
    colojeepguy

    colojeepguy Colorado Springs

    At the foot of...
    Joined:
    Apr 4, 2010
    Messages:
    7,275
    I have parts ordered from all over the place...new input shaft arrived yesterday.
    20220817_065803.jpg

    Waiting on a pilot bushing & a gasket set for the OD coming from AA, transmission gasket kit from PartsMike, clutch parts from Rock Auto, a couple gallons of GL3 90wt coming from Amazon, a new clutch cable from Inline Tube, and a driveshaft yoke from R&P in Oregon.
     
    Last edited: Aug 17, 2022
    wheelie, dnb71R2, Jw60 and 2 others like this.
  9. Aug 17, 2022
    Steve's 70-5

    Steve's 70-5 Active Member

    Louisville, Ky
    Joined:
    Nov 12, 2009
    Messages:
    1,386
    Th

    The cash register is ringing
     
  10. Aug 17, 2022
    colojeepguy

    colojeepguy Colorado Springs

    At the foot of...
    Joined:
    Apr 4, 2010
    Messages:
    7,275
    Still need a gasket set for the tcase, and I'll have to pay to get the lengths changed on my driveshafts.
    Probably a few other little things I've forgotten, but hopefully no more major $$$.
     
  11. Aug 17, 2022
    Jw60

    Jw60 Dropping towbars 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Trails end,...
    Joined:
    Apr 8, 2008
    Messages:
    5,023
    front yoke might make up most of the difference.

    T-90 8" case with 2.625" adapter... 10.625"
    T-18 11.875" case with 1" adapter... 12.875

    A little grinding wheel on the rear splines might be all you need.
     
    Last edited: Aug 17, 2022
  12. Aug 17, 2022
    Fireball

    Fireball Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Pullman, WA
    Joined:
    Feb 9, 2018
    Messages:
    5,846
    You'll need a front yoke for the transfercase and a whole new driveshaft for the front to go with the bigger U-joints.
     
  13. Aug 17, 2022
    colojeepguy

    colojeepguy Colorado Springs

    At the foot of...
    Joined:
    Apr 4, 2010
    Messages:
    7,275
    I have those.
     
    Fireball likes this.
  14. Aug 17, 2022
    Norcal69

    Norcal69 Out of the box thinker 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Northern California
    Joined:
    Sep 6, 2014
    Messages:
    3,648
    I would strongly consider upgrading to a CV drive shaft at this time. You will need to install a CV yoke on the rear output of the transfer case.
     
  15. Aug 17, 2022
    homersdog

    homersdog Tulsa, Ok 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Tulsa, OK
    Joined:
    Jan 8, 2012
    Messages:
    2,416
    Which brand of gear oil did you order from amazon?
     
  16. Aug 17, 2022
    colojeepguy

    colojeepguy Colorado Springs

    At the foot of...
    Joined:
    Apr 4, 2010
    Messages:
    7,275
    Sta Lube
     
    homersdog likes this.
  17. Aug 17, 2022
    Fireball

    Fireball Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Pullman, WA
    Joined:
    Feb 9, 2018
    Messages:
    5,846
    It doesn't really seem necessary with a D18, a T18 that's only 1.5" longer than the stock transmission, and a 2.5" lift.

    Not much u-joint angle on my '71 with this setup. The lower rear output of the D18 vs a D20 really helps:
    [​IMG]

    [​IMG]
     
  18. Aug 17, 2022
    colojeepguy

    colojeepguy Colorado Springs

    At the foot of...
    Joined:
    Apr 4, 2010
    Messages:
    7,275
    Can you post some detail pictures of your crossmember and trans mount, and also your clutch cable (if you're still using one)?
     
  19. Aug 17, 2022
    dnb71R2

    dnb71R2 SuperDave 2023 Sponsor

    Grand Mesa, CO
    Joined:
    Aug 13, 2006
    Messages:
    1,370
    Make sure the driveshaft/transmission/transfer case centerline is PARALLEL with the pinion yoke in the rear differential.
    This should have been marked somehow prior to disassembling the drivetrain.
     
  20. Aug 17, 2022
    Fireball

    Fireball Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Pullman, WA
    Joined:
    Feb 9, 2018
    Messages:
    5,846
    Yes this is important. Since i didn't have any driveline vibration prior to the swap, I matched the angle of the drivetrain before and after.

    Before with the T-14:
    [​IMG]

    After with the T-18. I got within 0.2 degrees:
    [​IMG]
     
    Stakebed, Muzikp and dnb71R2 like this.
New Posts