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Dana 18 Not Shifting Back Into 2h

Discussion in 'Early CJ5 and CJ6 Tech' started by jeepstar, Aug 14, 2022.

  1. Aug 17, 2022
    jeepstar

    jeepstar Well-Known Member 2022 Sponsor 2021 Sponsor 2020 Sponsor

    Sheboygan
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    Apparently not. Hard to believe though
     
  2. Aug 17, 2022
    dnb5853

    dnb5853 Member 2021 Sponsor

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    Glad you figured it out! :bananatool:
     
    Dwins1 likes this.
  3. Aug 17, 2022
    jeepstar

    jeepstar Well-Known Member 2022 Sponsor 2021 Sponsor 2020 Sponsor

    Sheboygan
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    Now, that locker is 5.38, for sure. And my front axle is for sure 5.38.

    So very soon I will know that I have 5.38 gearing, 100%!!
     
    Fireball likes this.
  4. Aug 17, 2022
    colojeepguy

    colojeepguy Colorado Springs

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    The 4.27s would be nicer on the street...
     
  5. Aug 17, 2022
    Jw60

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

    Sedalia MO.
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    5.38's and t90c with a 4cyl would be alright with an overdrive getting the final drive back to 4:10.
     
  6. Aug 17, 2022
    jeepstar

    jeepstar Well-Known Member 2022 Sponsor 2021 Sponsor 2020 Sponsor

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    I know, but I own a locker in 5.38.....
    I can put 4.27 in the front, but it's all new gears and everything else. And I'd have this locker just sitting around
     
  7. Aug 17, 2022
    jeepstar

    jeepstar Well-Known Member 2022 Sponsor 2021 Sponsor 2020 Sponsor

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    I've got a t98, FWIW.
     
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  8. Aug 17, 2022
    Jw60

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

    Sedalia MO.
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    4.27 and 5.38 should be the same series case front and rear.

    Oh my gosh :bow: how low can you go?

    Drive around town with the rear driveshaft removed and see if you like the 5.38 gears
    Now are you sure the rear splines are not 19 spline?
     
    Last edited: Aug 17, 2022
  9. Aug 17, 2022
    boopiejones

    boopiejones I can’t drive 55

    California east bay
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    i have an sm420 with 5.38 gearing and it’s LOW. On the road I start out in 2nd gear and am shifting into 3rd before I even get through an intersection. It’s fine for around town, but anything with speed limits over 55 is basically not happening.

    t98 has slightly higher 1st and 2nd gear, but 3rd and 4th are identical to the SM420.
     
  10. Aug 17, 2022
    Fireball

    Fireball Well-Known Member 2022 Sponsor 2021 Sponsor 2020 Sponsor

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    Did you get new 5.38 gears with it? The box is just for the limit slip itself. It needs gears to work. It's a series 4 limited slip so any gear ratio numerically higher than 3.92 would work. You could put the existing 4.27 gears on the new limited slip and re-gear the front to match.

    Also according to the part number your limited slip is 30 spline. Is this a '70/'71 flanged offset axle you're putting this in? If not, your axles are probably 19 spline and you'll need to install a 30 spline full float kit along with the limited slip.
     
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  11. Aug 17, 2022
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member 2021 Sponsor 2020 Sponsor

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    Glad you know the issue - it always is better when the problem is known and you can work toward the solution. But I might suggest slowing down for a minute and kind of assessing what you have and what you want to do. There are often multiple paths to good final drivable solutions, and the 'best' one may be as much about how you want/like it versus any other issue (say money, time etc), so take your time and ensure you do it the way that will be most rewarding in the long term. Again, I'd start with a simple inventory of what you have for each axle and diffs.
     
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  12. Aug 17, 2022
    3b a runnin

    3b a runnin Active Member 2023 Sponsor 2022 Sponsor 2021 Sponsor 2020 Sponsor

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    THIS
    Take out the front driveshaft and drive it while you think about it.
     
  13. Aug 17, 2022
    jeepstar

    jeepstar Well-Known Member 2022 Sponsor 2021 Sponsor 2020 Sponsor

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    Great food for thought. I'll sleep on it, but thinking I'll just swallow my pride, admit i made an expensive mistake, and get a 4.27 front axle setup.
     
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  14. Aug 17, 2022
    Fireball

    Fireball Well-Known Member 2022 Sponsor 2021 Sponsor 2020 Sponsor

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    Agree that's probably going to be the nicest overall setup. At the moment, you have the rare opportunity to try it with both gears back to back and see how you like it. You know how it drives with 4.27s when you are in 2wd. If you pull the rear driveshaft and put it in 4wd so the front is driving, you can see what the 5.38s are like going down the road.
     
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  15. Aug 17, 2022
    FinoCJ

    FinoCJ 1970 CJ5 Staff Member 2021 Sponsor 2020 Sponsor

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    And as mentioned above, the eaton truetrac you showed a pic of (D44 DET TT 4 30) will work for either 4.27 or 5.38, so you should pick which you like to drive better. BUT...the eaton looks like its for a 30 spline D44 rear axle. That axle and both ratios would have been original equipment on the 1970 cj5 4cylinder - so I lost track if that is the jeep we are talking about. Just make sure the eaton will work with current rear axle before committing to keeping the rear as is. It sounds like you have a good solution developing but avoid compounding a frustrating mistake with another one. Just to ask - do you have an OD? The OD might not be all the useful on a 4cyl with 4.27, whereas it would be much more useful with the 5.38s. If no OD, then 4.27 seems like a good way to go - and with the T98, you would still have plenty of low end crawl.
     
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  16. Aug 18, 2022
    jeepstar

    jeepstar Well-Known Member 2022 Sponsor 2021 Sponsor 2020 Sponsor

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    No
     
  17. Aug 18, 2022
    colojeepguy

    colojeepguy Colorado Springs

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    With a 4 speed, and no overdrive, I'd go with the 4.27 gears. Just my 2 cents.
     
  18. Aug 18, 2022
    kenb

    kenb Cleverly disguised as a responsible adult

    Detroit
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    I agree. With 5.38 and no overdrive it's frustratingly loud trying to go faster than 45
     
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  19. Aug 19, 2022
    jeepstar

    jeepstar Well-Known Member 2022 Sponsor 2021 Sponsor 2020 Sponsor

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    Here is what i was pulling with the jeep in 4WD and mismatched gears thru the woods
    Resized_20220817_161542.jpeg
     
    Fireball likes this.
  20. Aug 19, 2022
    jeepstar

    jeepstar Well-Known Member 2022 Sponsor 2021 Sponsor 2020 Sponsor

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