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Strange noise

Discussion in 'Chevy Trucks' started by eamims, Dec 26, 2002.

  1. eamims

    eamims Junior Member
    Messages: 20

    OK, I have a small crackling noise coming from the dash when I get moving (say above 30 mph). It sounds like tiny plastic gears with sand stuck in them. It's hard to pinpoint it because it only happens at speed, but it seems to come from the odometer area of the dash. There seems to be no relation to engine vibration, because it doesn't do it when it's not moving. Any ideas?

    thanks!

    eric
    '77 bonanza 350
     
  2. Got Grass?

    Got Grass? Senior Member
    Messages: 641

    Snow being sucked into the blower motor?
     
  3. Mike 97 SS

    Mike 97 SS Banned
    from U.S.A.
    Messages: 1,106

    Possibly a bad speedometer cable?? Mike
     
  4. Got Grass?

    Got Grass? Senior Member
    Messages: 641

    Good thought. Possibly the speedo cable conduit wearing out from rubing up against something.

    Does the spedo flutter a bit higher speeds?
     
  5. eamims

    eamims Junior Member
    Messages: 20

    Yea, I noticed it jump around 60 the other day. The speedo fluttered a bit (maybe 5-10 mph), but I haven't noticed anything repetitive with it and can't reproduce it. But, yes, it occasionally jumps. How can I check and/or correct such a thing?

    thanks
     
  6. Got Grass?

    Got Grass? Senior Member
    Messages: 641

    Chuck :help: ?
     
  7. Chuck Smith

    Chuck Smith 2000 Club Member
    from NJ
    Messages: 2,317

    Yes, it is most likely the speedo cable. The cable stops spinning, and the gear in the T case keeps spinning, thus, the grinding noise. The cable "telegraphs" the noise up to the instrument panel. I think a new cable is about $50 (last time I bought one). You should also check the gear in the T case, to see if it is damaged.

    Inspect the speedo cable, they typically run exhaust systems too close to the cable, which results in the cable sheath melting. It just gets worse and worse once the sheath is exposing the cable inside. When replacing the cable, it is easier to attach the end to the instrument cluster first, then to the t case. It is not an easy job the other way......

    ~Chuck
     
  8. eamims

    eamims Junior Member
    Messages: 20

    Where could a buy a speedo cable for a 1977 c-10? I checked the obvious sources (LMC, JCW, Classic Ind) and none had one. Where to check?

    ~~Eric
     
  9. Got Grass?

    Got Grass? Senior Member
    Messages: 641

    I did a quick search for one on www.autozone.com:
    PIONEER SPEEDOMETER CABLE for a 1977 CHEVROLET TRUCK C10 1/2 TON P/U 2WD

    Unit Price: $9.97
     
  10. eamims

    eamims Junior Member
    Messages: 20

    thanks for the quick reply. I'll check it out!
     
  11. Chuck Smith

    Chuck Smith 2000 Club Member
    from NJ
    Messages: 2,317

    Got Grass is right on. Any local auto parts store should be able to get it for you. Be careful of AutoZone. In my experience, their parts are the cheapest they can find, and not the best quality.

    ~Chuck