Chevy Suburban rear end clunk mechanic help

Discussion in 'Sound Off (' started by luv2havemoartime, Jul 7, 2009.

  1. I bought a 2003 Suburban and have noticed something recently-When I am coasting (foot of the gas and brake) around 15-20 mph like through a subdivision and then step back on the gas I get a clunk from the rear of the vehicle. When I baby the gas pedal, no clunk, but if I give it pretty good gas, (not nailing the gas) the clunk is there every time. U-joints were just replaced and the clunk is still there.

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  2. I have an 03 silverado with the same problem. My buddy at th dealership told me it was a fairly comon occurrence. I can't remember what the exact problem was.

  3. I would inspect the u-joints. Even at the cost of about 15 dollars per U-joint I would go ahead and replace them.

    Depending on what rear end you have. Will depend on what to do. Since you state you have new U-joints in the driveshaft.

    One thing is gear lash, if this is wrong that can cause a clunk. There are shims for the pinion bearing. If this is off that will cause your clunk. Also if your preload is off on the rear end that will cause your clunk as well.

    I don't know if there is one but if you have a carrier bearing on the driveshaft also referred to as a center support bearing. If that bearing is bad it will cause a clunk as you mention.
    #3 bigcountrysg, Jul 8, 2009
    Last edited: Jul 8, 2009
  4. It is the classic GM slip yoke problem. I had the same thing and took the drive-shaft out and put grease on the shaft that fits into the transfercase. I think what happens is when you hit the gas everything slides back a bit and the clunk is the driveshaft moving a bit. Regreasing the yoke cured the problem. It is a very easy job to do: unbolt rear u-joint and drop rear of shaft and slide the whole unit out of the transfercase. Then wipe the part that fits into the transfercase and regrease it. Put the whole thing back together and you should be all set. Just remember to mark how the unit came out so it goes back the exact same way it came out.
    Sorry for the long post but hope it helps.
  6. Mine has 119k on it. It's done it since I bought it, no problems yet.

    Knock, knock.
  7. very common problem.....only thing i have done to make it a little less noticable is replace the diff fluid with some good synthetic fluid.....i would rec. you use BG fluid and rear diff additive for the clutches if it has won't fix it but make it less noticeable.

  8. All 3 Chevy trucks I have owned did it. Every day, every time.

    Turn up radio or buy a MOPAR.
  9. All the trucks I have owned never had this problem. Oh wait that's right I have only owned 3 chevys in my lifetime.

    2000 silverado turned back in for refund through lemon law.
    1985 Chevy S-10 blazer, sold it with over 150,000 miles on it
    1982 Chevy Chevette, best dang running car ever owned. That thing went through hell. Sold it back when I was still in highschool.
  10. Does it do it in neutral coasting? If so Probably GM's sloppy rear end. They have been making them with the same wore out molds for over 30 years.
  11. stinger63

    stinger63 Banned

    It could posibly be the hole inside the housing where the ring gear pin goes in.They have a tendacy to get wallard out from the shifting into reverse.My 1994 van has the same problem.I also had an 81 chevy malibu with the same problem.I made a home made shim out of aluminum and stuck inside the hole and then slipped the pin back down inside.Never had another problem till I removed the 229 v6 and replaced with 350 chevy built tothe teeth then the whole rearend blew apart:lol:
  12. This is likely the problem. And it is not only a GM problem. When under torque, the slip yoke can lock up and prevent it form sliding in or out to account for suspension travel. This usually happens in older vehicles as the lubrication coating on the splines wears off. When the thrust force is enough to to overcome the friction, the yoke slides quickly causing a clunking sound. My 97 F150 does this when I am carrying a load or heavy trailer at between 40 and 45mph. If you can get at it and lube it, should go away, until the new lube wears off.

    Marking the unit is important if removing. Those shafts are balanced, and if you misalign them it could throw the balance out of whack. Last thing you want is the DS coming up through the floor when you are going 70 mph. I've seen it happen, it's exciting to say the least.

    Could, also, be something with the diff, like Stinger mentioned, but having seen a lot of these things, my first guess would be the slip yoke splines, especially since babying the throttle eliminates it.
    #12 brdhntr, Jul 9, 2009
    Last edited: Jul 9, 2009
  13. My '98 chevy with 165,000 miles on it has a clunk to it and always has, no problems detected even when a friend of mine a certified mechanic looked at it. I got so used to it that I will get worried when it STOPS clunking!!! :lol:

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