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Th350 Vs Sm420

Discussion in 'Intermediate CJ-5/6/7/8' started by Steve Ryan, Nov 9, 2021.

  1. Nov 10, 2021
    johneyboy03

    johneyboy03 The green beast

    Quebec, Canada
    Joined:
    Jan 15, 2011
    Messages:
    2,115
    Since i got the LS in....i'm about 2/3 of my gas consomption
     
  2. Nov 10, 2021
    Steve Ryan

    Steve Ryan New Member

    Foresthill,ca
    Joined:
    Jan 22, 2021
    Messages:
    10
    My ring gears are 3:73 IF i did it right ( counted wheel revolutions to drive shaft) havent pulled the diff. Covers yet to verify.
    I apologize for my grammar or lack of , I am a 60 yo const. Worker and have many bad habits lol
     
  3. Nov 10, 2021
    dnb71R2

    dnb71R2 SuperDave 2023 Sponsor

    Grand Mesa, CO
    Joined:
    Aug 13, 2006
    Messages:
    1,318
    This is where opinions will start to vary. JMO: The 3:73 ratio is great for the highway, but not so much for off-roading.
    Are you mostly trail running, cruising around town or do you have to run on the highway at faster speeds?
    If your tires are larger than 31", the Tera-low kit would be nice to have for off-roading even with the automatic transmission. Of course, you can always add that later after you get the basic rig running.
    I'm sure you'll get plenty of ideas here...
    This is why I encourage the owner/builder to make sure he/she knows what they want in the end with vehicle capability! Don't start with one plan and change it half way through.
     
    Steve Ryan, Fireball and ITLKSEZ like this.
  4. Nov 10, 2021
    ITLKSEZ

    ITLKSEZ Hope for the best, prepare for the worst

    Liberty Lake, WA
    Joined:
    Aug 13, 2015
    Messages:
    6,656
    T18 (for example)/teralow D20/3.73s nets a respectable 74:1, and it eliminates any need for overdrive for road use.

    Just for giggles, a TH350/stock D20/3.73s nets a CR of 18.9:1 before you factor in the torque converter. :poke:
     
    dnb71R2 and FinoCJ like this.
  5. Nov 11, 2021
    johneyboy03

    johneyboy03 The green beast

    Quebec, Canada
    Joined:
    Jan 15, 2011
    Messages:
    2,115
    that why i got to order a tera low for my th350/dana20 combo. i will get a 29.6:1 ratio, and if you factor a 2:1 torque you get a 59.20:1 ratio.

    With my t18/dana20 combo i never need to get more gear but now i have an issu.
     
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