2007 Jeep rear end rumble?

Discussion in 'KJ General Discussion' started by MarksmanAkula, Jul 6, 2020.

  1. MarksmanAkula

    MarksmanAkula Full Access Member

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    Ive researched this alittle bit, but i wanted some input from the guys here.

    Ive got a liberty that just got new tires, upper and lower rear end control arms, shocks, diff fluid, u-joints, the whole 9 yards. But i still get a rear end vibration at around 40-55MPH. I haven't tried highway speeds yet.

    Im lead to believe its a bad torque converter. If it is, do i need to replace the whole transmission? Or just the converter itself?

    Any help would be greatly appreciated!
     
    Last edited: Jul 7, 2020
  2. 03GoingStrong

    03GoingStrong Full Access Member

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    Here's one discussion on here about it ... or something similar
    https://www.jeepkj.com/threads/vibration-from-rear.55873/

    EDIT: Use the forum search for RUMBLE. The cause could be torque converter, wheel imbalance, wheel bearings and maybe a few others, but the most common was a bad rear U-joint in the drive-shaft. I'd check transmission fluid too. Might not help anything but wouldn't hurt to check fluids and costs nothing ... unless it needs changing or added to.
     
    Last edited: Jul 6, 2020
  3. 03GoingStrong

    03GoingStrong Full Access Member

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    ... one other thought comes to mind ... was it doing it before you did the "whole 9 yards" on the rearend. If not, maybe it's something associated with those repairs.
     
  4. tommudd

    tommudd Moderator Staff Member Moderator

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    Several things it could be
    tires are not always balanced correctly even at a """"" professional shop """"
    Rear LCAs, were they tightened with full weight on them, not hanging down
    U-Joints, make sure they are in the saddles correctly
    have found all 3 to make or cause issues over the years

    and as mentioned, when did it start ?

    is it lifted or is it sagged below new stock height ?
     
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  5. MarksmanAkula

    MarksmanAkula Full Access Member

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    Yes it was. It did it right from the start, and I thought it was the tires on the back causing it. As they were 2 different sizes. So I got new tires, still vibrates when under speed.
     
  6. MarksmanAkula

    MarksmanAkula Full Access Member

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    not lifted, stock height. Yes everything was tightened down with full car weight, and as far as I know the tires are/were balanced.

    what’s the thing with the U-joints though? I only replaced the one at the rear axle.
     
  7. tommudd

    tommudd Moderator Staff Member Moderator

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    replace the front as well
    I've removed them with only 50-55,000 miles that were rusted and wouldn't hardly flex any at all
    at least check it

    you mention stock height, so you have had the suspension replaced ?
    If not its sagged like Grandma was at 91
     
  8. MarksmanAkula

    MarksmanAkula Full Access Member

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    Where are the front U-joints? Coming off the transfer case I can only remeber there being one. Maybe I need to look again. EDIT - Yes there is a U-joint coming off the Tcase. Thats the only one i did not replace.

    but as suspension related yes it’s all 90% new. Only thing that’s not new is front struts and rear springs.
     
    Last edited: Jul 6, 2020
  9. 03GoingStrong

    03GoingStrong Full Access Member

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    How's the Liberty running? It's not a misfire at a certain RPM or anything causing shudder is it?
    ALSO ... at speed and when it's doing it ... if you shift into neutral, does it stop the "rumble" or has no effect and it keeps rumbling?
     
  10. MarksmanAkula

    MarksmanAkula Full Access Member

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    Runs perfect. Just replaced plugs and coils as it sat before i bought it. No misfire codes, no engine lights,etc.

    As for the shifting into neutral, ive never tried that. it commonly happens around 35-45MPH and if you keep a consistent speed while its happening, it will keep going until you either speed up or slow down.
     
    Last edited: Jul 8, 2020
  11. tommudd

    tommudd Moderator Staff Member Moderator

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    coilovers on front
    so all 4 springs and front shocks need done soon, may not be the problem but bet its bouncing off the bumpstops
    I've had them come into my place with 75-80,000 miles and be 2 inches below new stock height and riding like a buckboard

    what spark plugs?
    and yes there is a front u-joint up right behind transfer case
     
  12. MarksmanAkula

    MarksmanAkula Full Access Member

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    Plugs were NGK coppers. I know the engines dont like much else other than those.

    Bounce isnt bad, but it does need to be addressed at some point.
    Im 100% more concerned about the vibration over the ride quality
     
  13. 03GoingStrong

    03GoingStrong Full Access Member

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    I'm no mechanic, just an old guy who's owned a few LOL ... and I've forgotten more than I now know HA. I just figured if it still does it at speed, while in neutral, that might make me think more along the lines of drive-line and rear end than transmission and torque converter.
     
    Last edited: Jul 6, 2020
  14. MarksmanAkula

    MarksmanAkula Full Access Member

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    Theres nothing wrong with forgetting stuff, you and the gentleman on this site have been extremely helpful with any questions i, or other members have.

    I have a diagnostic appt with a transmission shop Thursday. Ill report back when i find out more.
     
  15. MarksmanAkula

    MarksmanAkula Full Access Member

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    So transmission shop said everything transfer case/Transmission/Torque converter was all good. They did recommend that i rebuild the CV joints on the front driveshaft though. Said one was gone and that may be a big cause of the binding or vibrations i was feeling.
     
  16. Gyro

    Gyro Full Access Member

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  17. MarksmanAkula

    MarksmanAkula Full Access Member

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