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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 14, 2022
    jeepstar

    jeepstar Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Sheboygan
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    My single stick dana 18 is giving me fits, and absolutely wont shift from 4h to 2wd.

    The back story: I was pulling a spring tooth in 4wd through the trails behind my house. Haven't walked them since I lost my dog. Needless to say they are overgrown and needed attention. Tractor normally does this work, but I also haven't touched it in over a year, and it wouldn't start, so I took the jeep...

    Its always been a smooth shifting t case.
    When I was done grading the trail I tried pushing the shifter lever all the way forward to 2wd, no good. Tried it in reverse, tried it while going forward. Tried it with the jeep off.
    I crawled under there and had the wife shifting it 4L/N/4H but wouldn't go into 2wd. Doesn't look like anything is impeding the 2 shift rails.
    Drove on pavement a short distance and it seems the back passenger wheel is also not spinning freely, it's kinda stuck and just gets dragged from the front axle.
    At a loss as to where to begin looking at what's wrong and what to begin to futz with.

    Thanks.
     
  2. Aug 14, 2022
    skipilot

    skipilot Member

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    Hmm…you might try jacking up the front or the rear just to be sure there is no binding between the two ends. A simple thing to try.

    Tim
     
    jeepstar and dnb71R2 like this.
  3. Aug 14, 2022
    wheelie

    wheelie beeg dummy 2024 Sponsor 2023 Sponsor

    York, PA
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    Disconnect the rear driveshaft and see if it’ll shift into 2H ????
     
  4. Aug 15, 2022
    kenb

    kenb Cleverly disguised as a responsible adult

    Detroit
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    Agreed. I've had trouble before getting out of 4H if the axles are binding. Would suspect this especially since you were doing heavy work in 4WD
     
  5. Aug 15, 2022
    jeepstar

    jeepstar Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Sheboygan
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    I'll put it on jack stands after work today first, see if that unbinds the axles.

    Why would the rear axle seem to not be spinning freely? I would think the front axle would be binding during revolutions since it's not shifting into 2wd?
     
  6. Aug 15, 2022
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    Maybe you broke a spider gear in the rear axle?
     
  7. Aug 15, 2022
    jeepstar

    jeepstar Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Sheboygan
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    Hope not. That wouldn't affect the 4wd shift though.
     
  8. Aug 15, 2022
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
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    One would think it wouldn't but, just remember the direct connection from the differential to the transfer case/transmission. I.e. drive line bind.
     
    Last edited: Aug 15, 2022
  9. Aug 15, 2022
    jeepstar

    jeepstar Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    Thanks. I'm home in an hour and will start by putting the jeep up on jackstands
     
  10. Aug 15, 2022
    jeepstar

    jeepstar Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Sheboygan
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    Here is my rear tire. You can see where it was scraping the pavement, not rolling freely.
    Resized_20220815_141952.jpeg
     
  11. Aug 15, 2022
    jeepstar

    jeepstar Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    So, I jack it up, put jack stands under it, engage the lockouts on my dana 30, spin the front tires, and all 4 wheels turn. I go into the cab, and the tcase shifts into 2wd WITH NO RESISTANCE.

    Thanks guys. Now, why did it do that, and how can I make sure it never does that again?
     
  12. Aug 15, 2022
    jeepstar

    jeepstar Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    All was fine up on jack stands.
    Put it down on the ground, test drove it in 2wd with the dana 30 lockouts set to free. Pulled over, engaged the lockouts, put T-case in 4, and the back was locked up/binding again, wouldn't shift to 2wd. On stands now, tcase slipped back into 2wd.
    Now when I spin my back wheel by hand, the drive rear drive shaft isnt spinning in sync with axle rotation and won't do a complete revolution.
    Spinning the front tire by hand in 4H with the lockouts engaged will spin my front drive shaft all the way around and the back drive shaft spins with it.
     
    Last edited: Aug 15, 2022
  13. Aug 15, 2022
    jeepstar

    jeepstar Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    Started it up while on the jack stands. one back tire and the opposite front tire was driving fine. (OPEN DIFFS, SO NOT A TRUE 4X4). Drive shafts were all spinning as they should as well.

    It goes in and out of 2/4wd no issues while on the jack stands.
     
    Last edited: Aug 15, 2022
  14. Aug 15, 2022
    jeepstar

    jeepstar Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    When the lockouts aren't in 4x4, the front driveshaft spins, tires won't turn. Lock them in, everything turns as it should. Shifts from 2 to 4x4 fine
     
  15. Aug 15, 2022
    jeepstar

    jeepstar Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    I'm thinking the transfer case is smoked?
    Only under load, or with the weight of the vehicle down on the pavement it gives me problems. It's off the jack stands, and with the engine off and no strain on the power train, it's going in and out of 2WD drive just fine
     
    Last edited: Aug 15, 2022
  16. Aug 15, 2022
    jeepstar

    jeepstar Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    Tried something else.
    Jeep on pavement.
    Engine off.
    Transmission in neutral.
    Lockouts engaged to 4x4.
    Shifted the tcase from 2H to 4H, pushed the jeep back and forth. No issues, shifts back into 2wd.
     
    Last edited: Aug 15, 2022
  17. Aug 15, 2022
    skipilot

    skipilot Member

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    I would investigate your rear axle a bit more, the dragging rear is worrisome. 2wd, trans in gear, jack up the rear. With an open diff, when you turn one wheel by hand, the other should spin in the opposite direction. Keep digging, you’ll find the problem

    Tim
     
  18. Aug 15, 2022
    boopiejones

    boopiejones I can’t drive 55

    California east bay
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    Maybe I missed it, but when on jackstands and you spin one rear wheel by hand, what happens to the other wheel? With an open diff, the other wheel should spin opposite direction.
     
  19. Aug 15, 2022
    jeepstar

    jeepstar Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    When I am in two-wheel drive and I turn one tire by hand, the other one turns in the opposite direction
     
  20. Aug 15, 2022
    jeepstar

    jeepstar Well-Known Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    I can drive in two-wheel drive all day no problem
     
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