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An Awful Screeching When I Let Off Gas Pedal?

Discussion in 'Early CJ5 and CJ6 Tech' started by Buildflycrash, Sep 4, 2019.

  1. Sep 4, 2019
    Alan28

    Alan28 Well-Known Member 2022 Sponsor

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    Yes a fan belt can make such noise.
     
  2. Sep 4, 2019
    Buildflycrash

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    I was thinking parking brake as well. I'll get in there tonight and check. Check the rear pinion and oil also.
     
  3. Sep 4, 2019
    Buildflycrash

    Buildflycrash More or Less in Line. 2024 Sponsor 2022 Sponsor

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    Eliminating possibilitys tonight. Checked the lube in front axle, transmission and TC. Changed the lube in rear axle. Shook the drive shaft as hard as I could and seems fine going into rear axle. Took apart the parking brake and the backing plate was fine. Surprised myself and remembered to drain TC before pulling the yoke. I had some on the shelf so I did put new brake shoes on parking brake. All this stuff was fine but now with 1000 miles since the rebuild it’s good to check it out anyway.

    One problem I stripped a bolt putting the shaft back onto the parking brake/ yoke. I really needed a new drum anyway so I’ll order that stuff tomorrow.

    Next I’ll look at the wheels and hubs.
     
  4. Sep 4, 2019
    Jw60

    Jw60 Sitting up n buckled down. 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    Stay cable? (Ducking)
    How is your rear pinion angle?
    Didn't you go to tapered T-case intermediate bearings? Do they need a 100mi follow-up?
     
  5. Sep 4, 2019
    ITLKSEZ

    ITLKSEZ Hope for the best, prepare for the worst

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    You really need to pinpoint front or rear, left or right... you (and we) could be stabbing at the dark for weeks. Take somebody with you. A second set of ears is always helpful.
     
  6. Sep 5, 2019
    Buildflycrash

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    No stay cable on this one
    It has a lift but Pinion angle doesn’t look crazy
    I only changed the front and rear seal on TC I don’t know anything about the inside.
     
  7. Sep 5, 2019
    Buildflycrash

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    I think we’ve eliminated a lot already.
    Not on engine because in neutral I can rev engine with no change
    Not clutch or transmission because clutch pushed in or out doesn’t change noise
    Not coming from front axle noise is definitely from rear of Jeep.
    Not parking brake. The parts looked perfect except not much pad left.
    Not dry because of low lube anywhere

    I think I’m left with rear axle. Pinion bearing or something to do with the hubs I just replaced. Or a TC bearing. Hopefully not there.

    Is the pinion bearing changed from the pinion area (drive shaft) or from inside the case?
     
  8. Sep 5, 2019
    47v6

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    jack up rear. put T/C in neutral. spin tires and find the bad axle bearing...
     
  9. Sep 5, 2019
    Buildflycrash

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    I just changed the outters and seals in the past couple weeks. Gotta go dbl check that work next.
     
  10. Sep 5, 2019
    47v6

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    Since you just changed them, I would look to that first.
     
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  11. Sep 5, 2019
    Glenn

    Glenn Kinda grumpy old man Staff Member

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    Both....inner and outer bearings.
     
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  12. Sep 5, 2019
    Glenn

    Glenn Kinda grumpy old man Staff Member

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    Can you jack the rear end up, put it on jack stands and run it while someone listens and maybe determines which side it's coming from? You sitting in it of course.
     
  13. Sep 5, 2019
    Buildflycrash

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    That's a great idea!
    If its not in my hub replacement work (which I need to recheck anyway) I'll definitely do that.
     
  14. Sep 5, 2019
    Framer Mike P

    Framer Mike P Member

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    I would look at the driveshaft u-joints as well - I have had some that screeched. You could shoot some grease into them to see if it would silence them - at least temporarily.
     
  15. Sep 5, 2019
    Buildflycrash

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    Those are new as well, 1000 miles, I did a visual and hand shake axle check but I'll grease them again for checking. Thanks
     
  16. Sep 5, 2019
    duffer

    duffer Rodent Power

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    My best guess also. In coast, any shot pinion bearings let the pinion move to the rear under coast where it can eat into the differential housing. Drain the gear lube and see it it has and metal in it.
     
  17. Sep 8, 2019
    Buildflycrash

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    Well it wasn’t in the parking brake. But since I had it apart I put on new pads and drum.

    [​IMG]
     
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  18. Sep 8, 2019
    Buildflycrash

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    I did exactly that today. We noticed the screeching started as the dust shield started spinning with the yoke. Seems it was rubbing against the outer pinion seal.

    [​IMG]

    Took u joint apart and pulled the yoke. The seal was crooked in the differential.

    [​IMG]

    So I’m sure I didn’t put this in crooked soooo

    The rear driveshaft is to long. I’m sure something else is going to break. Only about 1/4” of in travel when sitting on springs.

    With YJ springs How much “ in” travel should I have?
     
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  19. Sep 9, 2019
    Glenn

    Glenn Kinda grumpy old man Staff Member

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    Driveshaft is certainly too long, trying to figure out how it affected the dust shield though.
     
  20. Sep 9, 2019
    ITLKSEZ

    ITLKSEZ Hope for the best, prepare for the worst

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    The only way the driveshaft being too long could affect the seal or dust shield is if it bottomed so hard that it wiped out the outer pinion bearing with it (and probably the gears too) to allow it to move the pinion into the housing to press off the seal and shield. If the pinion bearings have proper preload and are in good shape, the driveshaft vs. dust shield can’t be related beyond coincidence.

    My guess is that the dust shield got bumped and came loose by the same stick or rock that got in there and wrecked the seal. Those dust shields are notorious for coming loose, usually for little to no reason.

    When setting driveshaft lengths, I usually work backwards. Drop the axle as low as it will go, plus have some kids sit on the wheels to get a little extra out if it. That’s where I usually set the tips of the male splines to be at the outer edge of the female splines (just to the point where no splines are exposed). Tack it all together and see what it looks like when the suspension is compressed. I like to have at least 1/2” of spline travel left at full compression to allow for variables. If you have less than 1/2”, cut the tube so you get that 1/2” and let the splines fall where they may. Working backwards like that lets you start “too long” and work your way shorter if needed, rather than having to source a new tube if it’s not right the first time.
     
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