98 GMC Sonoma 4.3L V6 2wd auto - loud low drone and loss of power

Discussion in 'Chevy S10 Forum (GMC Sonoma)' started by bradyxc, Sep 28, 2013.

  1. bradyxc

    bradyxc New Member

    I am new here and not a mechanic, but I want to do my own maintainence if I can. So to begin I have had my truck for three years now and the most major fix I have had to make is the fuel pump. However, when I recently moved to Colorado I started getting a low pitched loud noise. When idling the truck is nearly silent, but gets quite loud as the RPM's go up and more so when I'm accelerating. The oil and transmission fluid looks good and shifting is hardly noticable. The check engine light has been on, but that because the guy that replaced my fuel pump didn't get the connection leading to the gas cap sealed well and I can't quite get it there either. (P0452 code triggering check engine light) There is also a rough vibration accompaning the loud sound. When driving at 10 - 15 mph range there is a slow clank.
    Anyone have any ideas? I'm not sure where to begin looking. Could it be associated with the poor seal to the gas tank?

  2. Pikey

    Pikey Moderator Staff Member 5+ Years ROTM Winner 5000 Posts

    It could be a bad ujoint or possibly a bad midshaft bearing on the drive shaft (if that truck has a midshaft bearing) Does it make the sound in park when you hit the gas? If so I would check out the heat shields on the muffler. If it does not do it in park only drive, then I would block the front wheels, jack up the rear end, put some jack stands under it. Then start it up and put it in gear. Do you hear the noise when you let your foot off the brake and the wheels start turning? If not hit the brake and stop the wheels from turning. Put the parking brake on pretty hard. The point of setting the parking brake is to try to put the drive line under a load. Then put it in gear and give it some gas. Do you hear the sound now? If so, I would have a friend get in the truck and control the brake and gas, you crawl under it and start looking for the source of your sound. Please don't crawl under it if it is not on jack stands. Watch out for the spinning driveshaft! I doubt it is in any way associated with your bad gas tank seal

    I had a simulair issue with my 05 yukon xl. I took it to a trans shop and a rearend shop. They both heard the drone but could not figure it out. Last night I jacked up the rear and set the parking brake. I had my wife hit the gas. I found that the heat shield on the muffler was making a drone sound at certain rpms under load. I bent the shield up with a screw driver and the noise has stopped for now. It drove me nuts for a month.
  3. bradyxc

    bradyxc New Member

    Thanks for the recommendation. I'll try to check that tomorrow, at least it sounds like it shouldn't be too costly of a fix. I'll post back once I do check.
  4. bradyxc

    bradyxc New Member

    I've been busy so it took me a bit to have time to check. It does not make the noise in park. When I jacked it up and put it in drive (it was on jackstands), I could hear it just from idling speed. From outside the cab the sound was more metalic like a clanking and was coming from I believe the joint in the middle of the drive shaft. Based on the sound I'm guessing it is the joint rather than a bearing? Is this something that I can fix on my own? Or will I need to take it to a mechanic?
  5. Pikey

    Pikey Moderator Staff Member 5+ Years ROTM Winner 5000 Posts

    Depending on your skill level you may be able to do it. If it has the factory installed u-joints you will have to heat them with a torch to over 500 degrees to melt the plastic out. You can rent a ball joint press at any parts store to help get them out. Just be careful not to bend the yokes. I would not pound on the ujoint like he does. I would press them out.

  6. bradyxc

    bradyxc New Member

    I finally got around to attempting the fix and it turns out it isn't the u joint. As I said before I am not a mechanic so I didn't know that my truck actually has one u joint at the transmission and two double cardan joints at the center bearing and the rear axle. It looks like it is actually the pieces surrounding the ball in the rear joint that are shredded. So is this something that I would be able to fix? I found a part at O'Reilly that I think is the right part to fix it (Precision Double Cardan CV Ball Seat Repair Kit). Is that what I need? Or should I just take it to a mechanic?

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