On a Mission: 50mph rumble

Discussion in 'KJ General Discussion' started by SAString, Jan 31, 2018.

  1. SAString

    SAString Full Access Member

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    Hi All:

    I'm new to the forum, as I just adopted the '02 Sport from my daughter. She got my '14 Cherokee for Graduation! Thanks for all the advice!

    This was a Michigan KJ, so lots of rust. 128K on the Odo. I've been dealing with the "50mph drone" that rumbles from 50 to 55mph. It stops when I let off the gas and I can get it to happen on-off just by tapping the gas. So as long as power is applied to the drivetrain at 50-55mph it rumbles. I'm 90% sure it's in the front. Not like the 40mph growl from the rear diff on my other daughter's '02 limited.

    Based on everyone's advice:
    1. New drive shaft U-joints, packed the spline with grease
    2. New front Drive shaft, CV joints
    3. New aluminum wheels_ Balanced BFG tires
    4. New NGK plugs yesterday
    ..Nothing.......same rumble at 50.

    Bought but have not installed yet:
    Bilstein 4600's all around
    OME 926 and 948's
    New rear upper and lower control arms (originals super rusty)
    Dynaflow 2.5" exhaust/muffler (original super rusty)
    ......the above not expected to solve the rumble, just the ride :)

    I have not found any thread on this forum that provides an answer to the rumble issue. It seems it is very common.

    What do I try next?
     
  2. HoosierJeeper

    HoosierJeeper Gold Supporter/Admin Staff Member Administrator

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    What about the intermediate shaft up front?
     
  3. SAString

    SAString Full Access Member

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    (update: 10/17/18 Intermediate shaft and both CV axles replaced no improvement) Thanks HoosierJeeper. I appreciate the response. I'll focus on what it takes to replace an intermediate shaft. If this process is discussed in the forum, is there a "How To:" available? I have an appointment with the dealer tomorrow for the Airbag recall, so if it's a "not recommended" to do it yourself. I'll ask them for a quote. Otherwise, I'll tackle it.

    Thanks again,
    Steve
     
    Last edited: Oct 17, 2018
  4. HoosierJeeper

    HoosierJeeper Gold Supporter/Admin Staff Member Administrator

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    It's pretty simple. It's the shaft between the passenger side front CV and the diff. To check it for play, grab the inside "cup" of the passenger side CV and wiggle it. A little slop is ok but if you can wiggle it much or hear it clunk, then it's probably bad. Most part stores don't carry it, check eBay, get the least expensive one, they're all the same. Should be around $100.


    If you replaced the CVs yourself, the intermediate shaft is easy. Undo ball joints, axle but and tie rod to get the knuckle off, then take the clevis off then pull the passenger side CV off, it might take the intermediate shaft with it. If it doesn't, put a pair of visegrips on the intermediate shaft and lightly tap it with a hammer. Make sure to always pull straight with this stuff to minimize the chance of damaging a seal.
     
  5. SAString

    SAString Full Access Member

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    Thanks! I'll order the part (usually that is the first commitment to doing it yourself!). I'll let you know how it went. Hope to have it finished by the weekend of Feb.10-11.
     
  6. duderz7

    duderz7 Full Access Member

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    I found my shaft on Amazon from Crown mfr for less than 80 Buck and free shipping. Also I found it very beneficial to also removed the shock when I did mine, it clears your path for removal and replacement of axle and shaft.
     
  7. SAString

    SAString Full Access Member

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  8. duderz7

    duderz7 Full Access Member

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    You are correct, if you're doing suspension work any way, might as well do it at the same time. Also I put that part number (5066057AB) in Amazon, it's 81 and change with free shipping. Make sure and grease the splines and CV axle where they come together. I assume you are planning to replace the CV axle as well right? Get the reman from Napa, I've heard stories of others being the incorrect length.
     
  9. Cardhu

    Cardhu Full Access Member

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    still sounds like rear driveshaft to me. Put a couple hose clamps as Balance weights on driveshaft.

    Move them around and see if rumble changes. Baring that, remove rear driveshaft and put it in 4H and go for a run if your not convinced its driveshaft.

    Noise disappearing at coast has me convinced.

    If you were lifted I'd say pinion angle and do you have the JBA link extender?
     
  10. SAString

    SAString Full Access Member

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    Thanks Duderz7 and Cardhu:

    Duderz7: I've purchased the intermediate shaft, may as well do it while I'm in there doing springs and shocks. Didn't consider the CV axles, so I'll inspect the right one when it comes out before the shaft goes in.

    Cardhu: When I removed the rust and painted the shaft, prior to installing the new U-joints, I saw a weight welded on the front side of the tube. In the back there where two "nubs" perhaps where a balance weight was, or supposed to go if needed. Hmmmm? I packed the splines with grease and even did the rotate the shaft 180° trick. No change to the rumble issue. But yes, the quiet coast must be a clue. Tomorrow I'll put the heads of two hose clamps between those nubs. If no change then, I'll rotate them to various combinations until I detect progress. I'll let you know either way.

    Thanks everyone for your experiences and knowledge! (Cont'd on Page 2)
    Steve
     
    Last edited: Mar 13, 2018
  11. Cardhu

    Cardhu Full Access Member

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    If you think its thrown a weight, take it to a machine shop to have it balanced. Adjusting with 2 band clamps is only diagnostic in that if the vibration changes, you identified the problem area.
     
  12. duderz7

    duderz7 Full Access Member

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    It's where the intermediate shaft and CV axle come together that's the problem. Crawl under there and give the can shaped portion of the inner Right CV a wiggle to see if it has much play. I've heard of some that actually rust solid, which would also cause issues. Check your rear u joints and balance like cardhu said. I was able to feel play in my u joints once I got the rear wheels off the ground.
     
    Last edited: Feb 2, 2018
  13. SAString

    SAString Full Access Member

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    Update: The mission is still ON!
    Replaced the intermediate shaft (front axle) No change to the rumble/vibe at 50mph
    Bilstein 4600's all around
    OME 926 and 948's (It raised higher than I wanted (about 3", expected 1.5")
    New rear Moog upper and lower control arms
    Dynaflow 2.5" exhaust/muffler
    Added hose clamps to the Diff side of the rear prop shaft (nothing), moved to the front and rotated several times. It seems to change the speed which the vibe occurs, but it's still there. I'm removing the shaft and taking it to a shop for balancing tomorrow (another $150 !)

    Anyone have any other clues if this shaft balance still doesn't stop the shake? It seems at or forward of the TC/shifter area. But that's just a seat-of the pants guess.
     
  14. duderz7

    duderz7 Full Access Member

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    Let us know after the drive shaft, seems like your test may have indicated a potential culprit
     
  15. SAString

    SAString Full Access Member

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    Thanks Duders7:

    Drove it to the shop in 4W high. No rumble at 50, so...better. There are still NVH issues going on up front (motor mounts?). The rear shaft balance won't be done until Friday night. Do I need that big heavy harmonic balance disk on the front yoke?
     
  16. rockymountain

    rockymountain Full Access Member

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    Did you get an alignment?
     
  17. SAString

    SAString Full Access Member

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    Mission (not entirely) Solved! Inland Truck Parts did a great job balancing the shaft. I installed it Friday night and the 50mph vibe is (half) gone! I had the alignment done at 4WheelParts when the springs a shocks were installed. The camber/caster bolts were rusted solid and had to be replaced. I'm just glad the worst of the vibes is gone, now I'm going after the crazy rattle in the middle of the dash, and grinding out the rusted rocker panels. New coils coming in after getting a P0305 and P0355 code yesterday. Still can't get the idle smooth out, so may order new upstream O2 sensors if the coils don't help. This Jeep is sure keeping me busy!
     
    Last edited: Mar 13, 2018
  18. duderz7

    duderz7 Full Access Member

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    One mystery solved, move on to the next. Thanks for keeping us posted
     
  19. rockymountain

    rockymountain Full Access Member

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    awesome! good job and way to be persistent! Just know that it will never idle smooth, these never did. I'm not saying it is supposed to buck back and forth or anything but getting each and every little twitch out of it won't happen. I get a smooth idle sometimes when I change the plugs randomly for a few days.

    I'm gonna have to look around to see who can balance a driveshaft. My mirror shakes when hard on the throttle and just like yours it seems it is the "50 mph vibe".
    thanks for sharing!
     
  20. SAString

    SAString Full Access Member

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    It's been a while since I've worked on the drivetrain. Thinking that my issues were solved, proved to be short-lived. The 50 MPH vibration is back with a vengeance. I have to back-off the pedal to change the harmonic or it just gets worse! Up a hill at 50+ is unbearable.
    The balanced driveshaft and new U-joints seemed to help, along with the new front driveshaft and new intermediate shaft. $$$$ It's still there. I know the OME lift added about 2" and the pinion angles have slightly changed to about 2.1° apart, but this is the same shake as before. I'm tempted to think it could be the slip-yoke splines are worn (How do I check this tolerance?) Reason being, when I installed the shaft and packed the splines full of tacky grease, the vibes got better. Anyone rebuild a Transfer Case to find it helped the drivetrain vibration? What do I do about that big harmonic balance wheel on the slip yoke? Do they sell those new anymore?