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i need another gear

Discussion in 'Early CJ5 and CJ6 Tech' started by halfofmycj, Jul 19, 2007.

  1. Jul 19, 2007
    halfofmycj

    halfofmycj New Member

    asheville NC
    Joined:
    Jun 18, 2007
    Messages:
    1
    im building my 62 cj for crawling but would like to drive it on the road at reasonable speeds, i have the stock t90 3 speed in it and it just wont cut it for road use. Is there a four speed tranny with a low first and high fourth gear that would bolt up or would an over drive system do the trick for me
     
    halfofmycj, Jul 19, 2007
    #1
  2. Jul 19, 2007
    jzeber

    jzeber Well-Known Member 2022 Sponsor

    Morgan Hill, Ca
    Joined:
    Nov 15, 2003
    Messages:
    3,327
    First question and maybe I missed it, is what engine are you running?
    The SM420 or SM465 is a great trans behind the V6. They both have the granny 1st gear. An overdrive would help tremendously for the highway speeds.
     
    jzeber, Jul 19, 2007
    #2
  3. Jul 20, 2007
    J2H

    J2H Total Jeep Newbie

    Ladson, SC
    Joined:
    Jul 12, 2007
    Messages:
    28
    A 3 speed isnt good for the roads? I thought you get get up to 50 or so on it, thats pretty much avg speed.
     
    J2H, Jul 20, 2007
    #3
  4. Jul 20, 2007
    Warloch

    Warloch Did you say Flattie??? Staff Member

    Falcon, CO
    Joined:
    Mar 4, 2003
    Messages:
    5,473
    You need to account for the axle ratio as well as the tranny/OD. MOST 3 or 4 speed trannies will have a 1:1 final drive ratio. With 5.38s or 4.88s that is not going to take you much over the 50 MPH range - and that depends on the engine.
     
    Warloch, Jul 20, 2007
    #4
  5. Jul 20, 2007
    Mike C

    Mike C Member

    Austin, TX
    Joined:
    Feb 19, 2007
    Messages:
    743
    As noted above, you can get better advice with more info on your jeep.

    What engine do you have? What final drive ratio do you have? What size tire are you running? Assuming a factory T-case you should have a 2.56 low range which also dictates how much gear multiplication you have.

    If you have a V6, the SM420 and factory 3.73 with 31"-33" tires makes for a great on/off road setup. 4.27 and 35" tires would be pretty good as well. There aren't any real good candidates for 5 speed truck trans with OD because of their length and the 80" wheelbase of an early CJ5.

    If you have 5.38 gears and an F head motor, you are going to have problems on the road anyhow. Not enough power or RPM capability for highway driving IMO. Everybody who has the F head motor wants the T98 4 speed which makes it hard to find and $$$$.

    I'm putting a 3.0 Mercruiser in mine with an SM465 behind it and the new shorter Novak adapter. Currently I've got $500 invested in it and another $500 to be spent on the adapter. After parting with the outdrive on the boat, I hope to get back to $500. So think about what your goals are and how much coin you want to part with.
     
    Mike C, Jul 20, 2007
    #5
  6. Jul 20, 2007
    jzeber

    jzeber Well-Known Member 2022 Sponsor

    Morgan Hill, Ca
    Joined:
    Nov 15, 2003
    Messages:
    3,327
    I have 4:88's and the sm465 with an OD behind my V6. I can easily cruise on the highway at 60 - 65 mph no problem. Personally I wouldn't want to go much faster than that anyway and even 65 is pushing it a little.
     
    jzeber, Jul 20, 2007
    #6
  7. Jul 20, 2007
    panzer

    panzer Super Mod Staff Member

    Columbus, OH
    Joined:
    Dec 9, 2003
    Messages:
    1,245
    Here is what halfofmycj has listed

    Drivetrain: hurricane
    Axles: stock
    Wheels/Tires: 34/9.5/15
    Suspension trail master
    Other: exo cage, buckets, 4in lift, more to come
     
    panzer, Jul 20, 2007
    #7
  8. Jul 20, 2007
    sparky

    sparky Sandgroper Staff Member Founder

    Perth, WA
    Joined:
    Sep 20, 2002
    Messages:
    9,221
    He's filled in his profile with the pertinent information, click on the Year and Model to the right side of the postbit.

    Ok, so Panzer found it too. :beer:
     
    sparky, Jul 20, 2007
    #8
  9. Jul 20, 2007
    MOP

    MOP Active Member

    Pullman, WA
    Joined:
    Sep 25, 2003
    Messages:
    1,131
    An overdrive would do the trick, but your Hurricane may not.
     
    MOP, Jul 20, 2007
    #9
  10. Jul 20, 2007
    DanStew

    DanStew Preowned Merkin salesman Staff Member

    Lexington, South...
    Joined:
    Sep 22, 2002
    Messages:
    4,586
    It is a common misconception that you can go faster with a 4 speed. Unforunately there is no overdrive with a 4 speed. Usually you gain a granny gear that is great for offroading. A bolt on WARN overdrive would be your best bet for getting a bit more speed on the highway, but you are a touch limited with the Fhead. And if you are looknig for highway use, it is advisable to look into doing a brake upgrade because if you are going that fast with 34s, and if you have the stock 9 inch brakes, then you will be pretty unsafe on the highway if you need to panic stop.
     
    DanStew, Jul 20, 2007
    #10
  11. Jul 20, 2007
    SkysTheLimit

    SkysTheLimit Member

    Bend, OR
    Joined:
    Apr 27, 2006
    Messages:
    253
    I have the Dauntless in mine with (I'm assuming) the T-86 3-speed behind it with the Dana 18. I have 33x13.50 Pitbull Rockers and 4.27 gears in the axles, and I have the Warn Overdrive unit. I can go 65 on the freeway but my power steering is pretty twitchy so I feel like I might sneeze and jerk the wheel and roll it in the middle of the free way, so I usually tow it to where I wheel. Anyway, I guess my point is, with the setup I have, I can keep up with traffic with the overdrive without too much trouble.
     
    SkysTheLimit, Jul 20, 2007
    #11
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