Noise from rear end

Discussion in 'Chevy Truck Forum' started by Itstali25, Oct 20, 2005.

  1. Itstali25

    Itstali25 Senior Member

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    Alright, well lately my truck (86 Chevy 305 Auto) has been making a strange sound. It seems like the sound is coming from the rear end, its a whining that only occurs when i let off the gas. Suppose i have it in drive going 35 MPH and i let off the gas, it lets out a whine. I think it may be low fluid. I tried to put more in but the bolt on the differential is stripped. I tried to put the socket in there but it keeps slipping out. Is there anything else that might cause the sound? Is there a way i can get the bolt out? Is there a way to get fluid in there without taking out the bolt?? Thanks in advance.
     
  2. 390FE

    390FE Senior Member

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    One thing to remember is that the drive shaft can act as a sound tunnel making rear end noises appear to be in the front and vis-verse.

    Is there also a clunk when you get on and off the gas peddle. It could be as simple as a U-Joint or it could be wheel bearings or the gears(low on fluid). It could even be the tranny low on fluid or the fluid could be going bad if it hasn't been changed in a while.
    Those are my guesses.
     
  3. jrsrcvry

    jrsrcvry Member

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    I would try to remove the plug from the rear-end with a chisel. and make sure you replace it with a new one. I would guess that that was odvious but yhad to say it. Also try moving the driveshaft up and down at the rear-end see if there is any slop. It is usually that bearing there that causes it to whine.
     
  4. hotrod69

    hotrod69 Senior Member

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    Well Since Ihave Had This Problem Before It Is The Sound Of Pinion Slop On The Ring Gear. Even If You Change The Oil In The Diff The Problem Already Exists You Will Need To Have The Rear End Rebuilt Or At Least The Pinion Bearing Need To Be Replaced.
    It Doesn't Cost That Much To Rebuild Thankfully. As Far As The Plug You Could Take A Grinder To It And Reshape The Square Pattern On It To Get It Off, And Dont Use A Socket If It Is Hard To Get Off. Use A Tight Fitting Open End Wrench With A Breaker Bar A (mm)wrench Should Fit Tighter Than A Standard Size. I Say This Because A Wrench Will Have More Surface Area To Grab Than A Socket Will. And Yes Check Your U Joints Too They Probably Are Worn Out Also.
    hotrod
     
  5. chevyguy

    chevyguy Senior Member

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    Whining sounds like slop in the rear end. You should have a g.m. 10 bolt differential. The easiest fix would be to get an aftermarket diff cover with the plug in it. If you choose to repair your diff plug, then an easy out is my best suggestion after soaking it in penetrating oil. You may be able to buy alot more mileage bu replacing the fluid and adding lucas oil stabilizer. If you do decide to have it rebuilt this might be a great time to install the posi unit, of limited slip while you are in there.
     
  6. Itstali25

    Itstali25 Senior Member

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    awesome guys, thanks so much for the help, I'll try and get around to checking everything been kinda busy lately. How much money we talkin here Chevyguy for the posi?
     
  7. chevyguy

    chevyguy Senior Member

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    you just have to look them up. It depends on what type of unit you want and what gears you go with. Look on the net.
     

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