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What Do YOU think??

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by PattBlue, Jul 19, 2000.

  1. PattBlue

    PattBlue Registered Member

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    I have a 90 Blazer 350, 700 etc.. When I first got it the rear was sagging and a loud CLUNK was heard when you came to a stop. Today I had put 2" blocks on the back to level it and now it only CLUNKS some times and not as hard. I'm getting alot of different ideas..rear brakes sticking, spider gears, driveshaft to transfer case needs greased, pinion..?? It shifts okay and not alot of play in drive line. Don't thinks its U-Joints.. any ideas appreciated. Thats my project tomorrow.
     
  2. Hayduke

    Hayduke 1/2 ton status

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  3. MudFrog

    MudFrog 1/2 ton status

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    I have the same problem except my clunk is from the front, and it only happens when I hit a hard bump, or let off the gas after I first start off. I have checked everything I know to, from Engine Mounts, to U-bolts. I'm also stumped.

    89 K5 Silverado
     
  4. Chris Demartini

    Chris Demartini 1/2 ton status

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    <font color=blue>My 12 bolt clunks when i let off the gas (i have a stick) and i think its the spider gears. That might be whats making the noise on yours. My dad broke his this spring and they were making the same noise</font color=blue>

    http://www.chrisd71k5.coloradok5.com <font color=blue>Updated!</font color=blue>
     
  5. DMK

    DMK 1/2 ton status

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    My 89 did for about 2 years and it constantly got worse till the rear end went out. If there is alot of miles I would say its too much backlash. This will happen as the gears wear. Is there any noise.
     
  6. PattBlue

    PattBlue Registered Member

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    It only has 78500 miles (original) on it.
     
  7. Brian 89KBlazer

    Brian 89KBlazer 1/2 ton status

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    If you still have the stock rubber bushings, I'd check the spring and shackle bushings. Sounds like a rotten/deteriorated bushing and the leaf could be clunking around under braking.

    Good Luck
    Brian
    89KBlazer
     
  8. behemoth

    behemoth 1/2 ton status

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    My '78K5 does that (clunks) as I'm slowing for a stop light/sign. Then as I begin to accelerate, it'll do it again. I haven't gotten into it yet to figure out what's wrong, but ALL of you guys have given me ideas as to where to start. I appreciate that! THANKS!

    behemoth K5
     
  9. BigBurban

    BigBurban 1/2 ton status

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    I think I know exactly what you're talking about. It happens about a half second after you've come to a complete stop right? I've had this happen on two different trucks. I replaced the spring & shackle bushings and it fixed the problem in each instance. Hope this helps...

    <font color=blue>~BigBurban</font color=blue>
    [​IMG]
     
  10. 89K5

    89K5 1/2 ton status

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    I have 4" springs in the rear, still clunks when I let off the gas. Its been doing it for over two years. Got pretty bad BEFORE the lift and 35's, but hasn't broke yet.
     
  11. 4x4blazer

    4x4blazer 1/2 ton status

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    My '84 did somethin like this a while back. I discovered that the right rear shock, upper poly bushing had managed to squeese out a little from the housing. WhenI would brake or accelerate hard it would contact the mount bolt and make a "clank" noise. I pulled the top mount bolt out, added some thick washers on each side of the bushing, put it back together, and it solved my problem.

    But my rear u-joint lost some needle bearings once and I waited to long to replace it. I ended up with a blown rear end. It made a "clunk" sound too when I would start or stop.
    It made an even louder "clunk" sound when the rear end let loose at about 50mph. haha
     
  12. PattBlue

    PattBlue Registered Member

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    BigBurban,and Brian 89KBlazer, I think your both right. After adjusting the brakes..greasing all I could tonight time to buy some bushings..Thanks!!
     
  13. PattBlue

    PattBlue Registered Member

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    I know its almost a month later but that work thing did it...Now I'm on vacation so time to do the fun work. Anyway after seeing all these ideas and bugging the guys at the local GM dealership one guy GAVE me some "GM Special Purpose Grease" Sounded weird but had to try. Took the driveshaft off, cleaned the front yoke with a rag and applied HEAVY "GM Special Purpose Grease" to the yoke teeth and a light film on the exterior. Drove down to the local Beer Disturbitor to get a new 1/4 keg for the garage refrigerator, and WOW!! no clunks!! Thank-you all, but had to go back to the maker for this one...who would have thought Special Purpose Grease....sounds like the old-time cure all medicine show drinks.
     

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