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roaring rearend

Discussion in 'Chevy Trucks' started by Clemens, Jun 21, 2003.

  1. Clemens

    Clemens Junior Member
    from Europe
    Messages: 9

    on my 81 G30 van I have a full floating rear axle with a limited slip differential and there seems to be something wrong with it as whenever i exceed 50 mph there appears a loud roaring noise which won´t go away till i reach 80 mph; it´s louder when coasting, a bit better under full load, and an overall pain in the ass;
    it started like 2 years ago when i was driving with littel fluid in the rear axle. i checked the ring and pinion which are a little worn, filled the rearend with new fluid, had the drive shaft balanced and got a new bearing for the drive shaft, checked the yoke nut (it is tight) and noticed some play in the wheel bearings;
    another thing that i noticed which could have the same source as the noise itself is that when i accelerate very hard from standing still i feel some sorta vibration, which i do believe could be based on the worn ring and pinion not ling up perfectly.
    in my opininion i guess the noise comes from the worn gears, but some other people i talked to rather think it could either be the wheel bearings or the outdrive shaft bearing inside the tranny (TH400).
    as this ride is not my main project, i don´t wanna dump too much money into it. so just replacing parts till i solve the problem just won´t do it.
    thanx in advance
     
  2. BWhite

    BWhite Senior Member
    Messages: 496

    pinion diagnosis

    are you accelerating-coasting(floating)- or decelerating - or it all the time as a rear end trouble shooting chart requires this information
     
  3. SCFALL

    SCFALL Member
    Messages: 47

    NOISEY REAR END

    My 91 K 1500 Did the same thing it was bad carrier bearings took out the shims also . Scott
     
  4. Pelican

    Pelican 2000 Club Member
    Messages: 2,075

    You said you had the driveshaft balanced, were the u-joints replaced? Sounds to me like one of them may be bad.
     
  5. wyldman

    wyldman Member
    Messages: 3,265

    I'd also suggest you look at the u-joints first,then the carrier bearing.They are much more common than an expensive rearend repair.The tailshaft can be easily swapped to repair the extension housing bushing if it is sloppy.


    A worn ring and pinion WILL NOT vibrate unless you have other problems,like a pinion or diff bearing loose.
     
  6. jlsanborn

    jlsanborn Member
    Messages: 34

    sounds like u-joints to me.
     
  7. Clemens

    Clemens Junior Member
    from Europe
    Messages: 9

    i think i had both U-Joints replaced;

    hey, SCFall, what´s the carrier bearing (where is it)?

    as for your Question, BWhite, it´s apparent all the time above 50, but sometimes goes away when going uphilll and it´s worst when cruising downhill;
    during acceleration it is almost gone, but when letting off the gas it get´s really loud.
     
  8. wyldman

    wyldman Member
    Messages: 3,265

    The carrier,or hanger bearing,is pressed onto the driveshaft and bolts to one of the frame crossmembers to help support the driveshaft.Also check to make sure the driveshaft itself is straight and undamaged,and has not lost any weights.

    Even if the u-joints have been replaced they may be dry,or improperly installed.Double check,and grease them.

    If it's not one of the above,it may be the pinion bearings,but you would most likely be able to feel any roughness or play in them if they are that bad.You say it is accompanied by a vibration,so you would think if it is a diff problem,you would be able to find something loose

    One last thing could be tires.Try rotating them front to rear to see if the noise changes.
     
  9. Pelican

    Pelican 2000 Club Member
    Messages: 2,075

    Sure sounds like a U joint, a bearing would make noise but not produce a lot of vibration, unless the carrier like wyldman mentioned.
     
  10. Clemens

    Clemens Junior Member
    from Europe
    Messages: 9

    the carrier bearing is brand new, and the vibration is only apparent when accelerating very hard from standing still, but disappears once you hit 20mph or so;
    it´s driving me NUTS! :mad:
     
  11. wyldman

    wyldman Member
    Messages: 3,265

    If your positive it's not the u-joints,then I'd be double checking the carrier bearing,and driveshaft phasing and alignment.Maybe when the u-joints or carrier bearing was done,it got out of phase,or out of line ?

    You can visually inspect the shaft,to make sure all the joints are in line,and in-phase.If they are just a little bit off (at the slip yoke),you will get a vibration at low speed on accel.The driveshaft should also be straight from side to side,by adjusting the carrier bearing.You can also shim,or remove shims from under the carrier bearing to adjust alignment as well.

    Make sure the u-joints are all seated properly in the yokes,and there is no play in the extension housing bushing or slip yoke.

    Give the pinion bearing's a double check as well.Grab the driveshaft and see if you can move it up and down at all.
     
  12. Alan

    Alan PlowSite.com Addict
    Messages: 1,393

    One of us is confused

    Clemens,

    Somebody seems confused here.

    In one post you say "it´s apparent all the time above 50, but sometimes goes away when going uphilll and it´s worst when cruising downhill;
    during acceleration it is almost gone, but when letting off the gas it get´s really loud."

    Then in a later post "the carrier bearing is brand new, and the vibration is only apparent when accelerating very hard from standing still, but disappears once you hit 20mph or so;"

    So, which is it or are you just pulling chains here?

    There's a lot of help here for honest problems but I'm starting to be a bit suspicious about yours.
     
  13. wyldman

    wyldman Member
    Messages: 3,265

    Alan

    I think he was referring to the noise,or roar when he said..........

    Whenever i exceed 50 mph there appears a loud roaring noise which won´t go away till i reach 80 mph; it´s louder when coasting, a bit better under full load.

    And referring to the vibration at low speeds..........

    When i accelerate very hard from standing still i feel some sorta vibration.

    and again,the vibration at low speeds.............

    The vibration is only apparent when accelerating very hard from standing still, but disappears once you hit 20mph or so.

    Hopefully we'll get an update soon.
     
  14. Clemens

    Clemens Junior Member
    from Europe
    Messages: 9

    wyldman is right; the noise is apparent at higher speeds, the vibration only under hard acceleration below 20mph.
    i´ll try to recheck all u-joints and rotate the tires and inspect the driveshaft for straightness;
    as soon as i´ll find something out i´ll let ya know. :waving:
     
  15. wyldman

    wyldman Member
    Messages: 3,265

    Any updates ?
     
  16. Clemens

    Clemens Junior Member
    from Europe
    Messages: 9

    well, i´ve been on vacation for 3 weeks but i think i was able to trace down the source of the noise; i feel it comes from the carrier bearing which seems out of alignment and i´m about to realign it and see how things turn out. i´l keep you posted...
     
  17. Clemens

    Clemens Junior Member
    from Europe
    Messages: 9

    Update

    it´s been a while, but the problem remains...

    I removed tzhe driveshaft, checked the U-joints, the main bearing, realigned the driveshaft, put some new grease onto everything, but yet the problem remains.

    there´s still some vibration under hard acceleration from standing still and this roaring sound above 50 mph.

    at least i was able to locate the area where the noise seems to come from; it comes directly from underneath the rear seats, which means it should be in the area of the main bearing or eventually the tranny.

    could it eventually be one of the tranny´s bearings?

    slowly this is driving me mad...

    :mad:

    thx, clemens
     
  18. wyldman

    wyldman Member
    Messages: 3,265

    Is there any play in the output yoke at the trans ? Maybe the extension housing bearing is shot.
     
  19. Rick Loncosky

    Rick Loncosky Senior Member
    from 17557
    Messages: 102

    I'd say it's the pinion bearing(s), I had a 3/4 van that was noisy and that solved it. Good Luck...... :)