Strange noise

eamims

Junior Member
Location
Nashville
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
 
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eamims

Junior Member
Location
Nashville
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
 

Chuck Smith

2000 Club Member
Location
NJ
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
 
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eamims

Junior Member
Location
Nashville
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
 

Chuck Smith

2000 Club Member
Location
NJ
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
 
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