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Humming from rear

Discussion in '80-Series Tech' started by 410225, Oct 22, 2003.

  1. 410225

    410225

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    I found out about the humming. It is a rear differential.
    I bit my bullet and took it to the Toy Stealer. Checked out that rear differential is bad but not severe enough to replace it. What the heck is that mean? :mad:
    To recap what is going on, I heard a humming sound over 65mph driving hwy.
    So, what to do what to do...... Stealer said it would be close to $2500 to replace.
    I am going to drive it since it is not severe to NOT drive according to them.
    What do you guys think? Am I SOL?
     
  2. landtank

    landtank SILVER Star

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    Gears can break but as a DD it would most likely just start getting louder and louder until your ears began to bleed :eek:. No big rush on your part as this process could take a while depending on how much you drive. You could save quite a bit on that 2500.00 price. There is a thread in the sales area that myself and a couple others are offering there used but good gears sets for sale. Mine are from a gears swap to 4.88s so they are perfectly good and I imagine the others are the same. A set of those gears and a couple bearing kits and a competent local mechanic should have you back in shape for about 1400.00 total front and rear.
     
  3. AZcruiser

    AZcruiser

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    What kind of humming, I posted a while back the same problem. I get the most humming in 45-60mph range, really noticeable. Do you have alot of play inthe drive shaft(s) meaning .25" + about he axis? This weeknd I plan to remove the front and rear drive shaft to pinpoint the hum. I took it in to a shop they said the bearings(inner/outer and side) are bad.

    Chris
     
  4. landtoy80

    landtoy80

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    Is it the gears or just worn bearings???
    If its just worn bearings, just rebuild or have a shop rebuild. I rebuilt my front and need to do the rear sometime. There was no noise when I rebuilt. If you can find someone that has done it before it will save you big $$$.
     
  5. Beowulf

    Beowulf

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    >.> What do you guys think? <<

    Adrian,
    I think that if you change your ID one more time I'm gonna come to Minnesota and slap you upside the head. What's this now, the 4th change? ! ?
    :D
    -B-
     
  6. 410225

    410225

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    Sorry about that.... I did not mean to......
     
  7. Cruiserdrew

    Cruiserdrew SILVER Star

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    Wow-$2500 is outrageous even for a dealer. If you are certain it isn't something easy like wheel bearings, u-joints or tires, and you have a bit of mechanical aptitude, you can drop the diff and take the 3rd member to a differential shop and have them rebuild it. Your R&P is probably ok if it has ben serviced well, but the pinion and side bearings (usually pinion) can wear out and hum. I'll bet for $400 and a bit of work, you could be back on the road. Even if you need a new R&P, $250 will fix that, although real OEM Toyota gears are much more expensive. Toyota used to sell the entire third member brand new for about $900. You might check with CDan on this board.

    Pulling the third member is super easy on the full float axle-pull out the axle shafts about 6 inches, undo the driveshaft bolts at the pinion flange, take out the 12 bolts and carefully(!) lower the third member out of the axle housing. You might have to slightly jack up on the nose of the diff housing to break the seal initially. Seriously, this is only a few hours work, don't let them hose you for $2500.
     
  8. IdahoDoug

    IdahoDoug

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    I don't buy it. What kind of miles do you have, MN? What, specifically did they do to "check" the differential? If they pulled the rear cover off and examined the wear pattern that's one thing, but if they're just doing this "seat of the pants", then I'd be wary.

    Doug
     
  9. Desertmaster

    Desertmaster

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    MNCruiser, if a Toy Dealer checked the rear diff, they must have explained on paper what exactly is the problem (like which part that is causing the hum), if they did not, ask for the master mechanic @ the dealer look at the rig again and confirm the worn part or parts.

    The word Rear Diff is bad but not enough does not tell me or any body much.

    Hope this helps

    Al
     
  10. 410225

    410225

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    Hi,
    Thanks for the replies.
    I am not going to bring to dealer again to spend $49 JUST looking at the rig.
    I just went to my local drive train rebuild shop and they told me they can re-build the rear diff for $650.00. He knew the symptom, he knew what to look, and he has done LC before.
    I am also looking into another route of getting used rear diff from junk yard and just replacing it myself. I guess it is known as "Carrier Assembly".
    What do you guys think?
    Dealer is now out of site since they are to be PROVEN now a STEALER!
     
  11. AZcruiser

    AZcruiser

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    Whats the symptom?? any details
     
  12. 410225

    410225

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    AZ,

    humming happens while driving from 65mph and up. Gets louder higher speed. Let the foot off the gas pedal, you don't hear it. It happens only under the load.
     
  13. IdahoDoug

    IdahoDoug

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    MN,

    At the risk of repeating myself (heh), I'll again ask "how many miles do you have on your truck?"





    Then I'll leave lots of screen space so you see that question. The reason I want to know is that 80 rear diffs are stout, and I'd suspect a rear shaft issue WAY before a rear diffy - unless there's been some abuse/neglect.

    Doug
     
  14. DanKunz

    DanKunz SILVER Star

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    I prefer my humming in the front end ::)


    *runs away*


    edit for actual tech:

    I would also suspect driveline right now...grease everything up, check t-case fluid level and condition, maybe even change it to see if you see metal on the plug.

    Do the diff too...check the drain plug for metal.

    If you find metal, you probably found your problem.

    Easier than tearing everything apart for now.
     
  15. MTNRAT

    MTNRAT

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    Adrian, the $650 is more realistic. My local mech, put in 4.88s and replaced the rear brakes for $384 cdn. As for new ring and pinion, there are lots of us with perfectly good gears. So if it is that, don't buy new unless you want an excuse to go to 4.56 or 4.88. :D :D
    Sean
     
  16. semlin

    semlin discouraged user

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    What exactly is wrong with your diff? Get an explanation man. I hum at 80 mph plus. It may be a warn diff, it may be a lot of things. I don't like the sound of this mechanic who "knows" LCs and "knows" about the diff, especially if you told him the dealer's diagnosis beforehand. Been there, done that. Get him to explain it to you. Post the explanation here.
     
  17. IdahoDoug

    IdahoDoug

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    MN,

    I think many of us feel this is not right. 80 rear diffs don't wear out unless they've been neglected, AND have oversize rubber, AND are run hard on the trails. Something's fishy in Denmark here and I hope you're listening to your bro's here....

    Doug
     
  18. 410225

    410225

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    I hear ya, I know. I have 97 LC with 113k mi with lockers. I did re grease the crap out of all spiders, driveline. I checked the diff plug and fluid. Clean and no metal. I am suspecting
    1. Rear diff - Door knob dealer advised. So I had this checked by local diff shop.
    2. Tire - I have stock size but have not rotated. Maybe I'll try this.
    3. Drive shaft(Propeller) balancing issue. Will the unbalanced drive shaft make humming under the load?
    4. Exhaust hitting something and vibrating - I had this checked and welded all the broken hangers and nothing. Still humming exists.

    I really appreciate your help to pin point the issue and all my ears are yours to listen to your advise.
     
  19. cruiserman

    cruiserman

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    $650 had better include new ring and pinion and bearing kit, or it's Canadian dollars.

    Pull the 3rd member and take a look at it yourself. Be careful removing it from the axle housing. It's heavy.
     
  20. semlin

    semlin discouraged user

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    Adrian you have got to focus. We have been through these other suggestions before.

    Right now two mechanics have looked at it and told you it's the diff. We're not saying they're wrong, we're just suspicious. Let's give them the benefit of the doubt and start with getting the drive shaft mechanic's explanation of why he thinks the diff is bad and what excatly is bad (e.g., what parts). If he won't explain it then forget him, and call back to the dealer and ask for an explanation from them as to exactly what is wrong and needs replacing. They charged you $50 so they owe you that much.

    Report back and we will comment.
     
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