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Rear end noise

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Scott73, Dec 6, 2002.

  1. Scott73

    Scott73 Registered Member

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    I have an '87 K5 w/ 4" lift and 33's. A few months ago I went from 3.08 gears to 4.10s. When I first drove it home the truck made a growling noise when I let off the gas at around 65-70 mph. Now, it will do at speeds as low as 35 mph (sometimes). It has also started making a growling noise at speeds above 60 without letting off the gas. It won't always do it. Sometimes it will growl for a little while and then quite down and sound fine, and then a little later start growling again. Any ideas?
     
  2. Whoever did your gears messed up /forums/images/graemlins/rolleyes.gif Your gears aren't meshing correctly. Either you have a bearing that's going out or it wasn't shimmed right. In either case, take it back to whoever did it and let them test drive it while you're in the vehicle with them. Mine had the same noise when I had my gears changed and the guy fixed it free of charge even though it had been almost a year and 10k miles since he worked on it.
     
  3. TXsizeK5

    TXsizeK5 1/2 ton status

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    Can you describe the growl? I have some noise when I let off the gas when I drive on the freeway at like 70mph at 3k rpm in 3rd gear. Like its kinda like huge wind noise or like getting two peices of sheet metal and kinda rubbing them together....
     
  4. pilgrim

    pilgrim 1/2 ton status

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    yeah like he said, i bet the guy who did the gears didn't get them right. i did mine on my 10 bolts, i went from 3:42 to 4:56. little did i know (first time) i switched the shim rings on the carrier from one side to the other. well i thought things were going good until after a test run of a few miles, i got out to HEAR the oil BOILING /forums/images/graemlins/shocked.gif in the pumpkin. gears meshed to tight /forums/images/graemlins/smirk.gif ...
     
  5. TX Mudder

    TX Mudder 1/2 ton status

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    Umm.....
    So what did you do?
     
  6. Scott73

    Scott73 Registered Member

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    That sounds similar to what mine's doing.
     
  7. Dale fan

    Dale fan 1/2 ton status

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    Maybe someone can lead me in the right direction on mine. I've got a 90 all stock with 31's on it. It only has 75K on it, never been mudded or off roaded hard, a doctor had owned it, but it had been sitting up for about a year. I'm getting a roar in my rear while on the gas, it stops when I let off. Kind of sounds like tires singing but these tires won't sing, lol. The only time I get any noise without giving gas is when I roll to a stop, somewhere between 10-15 mph. Any ideas? I just hate to take it to somewhere and get raped for a bunch of crap (like new ring & pinion gears) I probably don't need. By the way this looks like an awesome site, I'm glad I found it.
     
  8. BowtieBlazer

    BowtieBlazer 1/2 ton status

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    I'd start by checking the gear oil in yours, chances are if it just sat up it just needs a fluid change. Even using a heavier weight oil say 85w 140 would work well to quiet any excess noise. Its as easy as unbolting the ten bolts on teh rear cover and draining the fluid, sealing and bolting the rear cover back up and refilling the diff with fluid.
     
  9. MA87K5

    MA87K5 1/2 ton status

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    The noise might be also coming from the x-fer case. Try it in 4 wheel and listen it might be more noticable.
     
  10. Dale fan

    Dale fan 1/2 ton status

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    Well I checked all the fluids as soon as I got it home. The front diff was fine and the transfer case was too. The rear diff was about a 1/2 quart low which I topped off. As for the four wheel drive, it doesn't seem to make a difference whether it's in or out. I may try to drop the rear drive shaft in a few days and see if my noise dissappears.
     
  11. Highlander

    Highlander 1/2 ton status

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    I would have to say the pinon bearing is going south. Wehn I got my 83 it make a noise at highway speed only when you were on the gas and would quit when I was off the gas as time went on it got worse. Right now I'm look at what to do with it. Do I rebuild it or get a 14b.
    One thing I did do for it was use some lucas gear oil or maybe it's call heavy duty oil stabelizer something like that. you can find it at NAPA or a truck stop the stuff is thick real thick. this time of year isn't great for it but if you used one bottle and the rest like 90/140 you should be ok unless it's 40 below.

    Eric
     
  12. Z3PR

    Z3PR Banned

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    </font><blockquote><font class="small">In reply to:</font><hr />
    Do I rebuild it or get a 14b.

    [/ QUOTE ] Get the 14 bolt FF !!!!!!!!!!!!!! /forums/images/graemlins/thumb.gif /forums/images/graemlins/thumb.gif
     
  13. Highlander

    Highlander 1/2 ton status

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    That seems to be the standard answer.
    I don't know if you saw my post about this whole thing, I e-mailed ARB they sent me a parts list and said most of everything for it I can get.
    But I saw a post where someone is make stuff to put 6 lug wheels on a 14b.
    Oh where is Blackhawk at?

    Eric
     
  14. Dale fan

    Dale fan 1/2 ton status

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    I agree on getting the 14 but budget won't let me handle that quite yet so I'm going to fix a few minor things and then go for the lift and axles swap. I noticed today that when the tranny or the transfer case is put into neutral the noise will stop. However that's only going forward, while in reverse about 15-20 mph, you get the noise and going into neutral and coasting won't stop it. I'm getting pretty positive it's in the third member, I just hope it's a bearing and not the gears. I'm going to pull the cover today and if it doesn't have metal swimming around it's going to the woods. Last 2 weeks of deer season down here. Shoot, I may just drive it until it blows or locks up then I'll have a good reason to buy new axles. By the way, I'd like to know about the 6 lugs with a 14 bolt, got tons of good sixers around here but 8's are hard to come by.
     

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