Strange Noise

[jbrignac]

Hopefully one of you may have come across this and could give me some advice. I've got a loud clicking noise that sounds like it's coming from the center or right of center of my dashboard. It doesn't have a pattern and the best description I have is a toggle switch being flipped. Only starts above 20 MPH and gets louder and more consistent as I speed up but goes away if I slide the truck into neutral so it's only there under load.

This is my DD so I'd really like to figure out what this is before it breaks but I'm stumped!

Jeremy

[midniteblues]

i know you said its coming from under the dash,but are you sure its not a exshaust manifold leak sure sounds like it the way you descibe it.

[Stocker]

Another possibility is a failed u-joint. Sound can travel and make it hard to tell just where it's coming from.

[Dunenutt]

Speedometer cable?

[custom1970]

Originally Posted by dunenutt

speedometer cable?

x2

[Stocker]

Originally Posted by Dunenutt

Speedometer cable?

Originally Posted by jbrignac

goes away if I slide the truck into neutral so it's only there under load.

Anything's possible, but I wonder if a bad speedo cable would go quiet when coasting... ?

[ChevLoRay]

Easy way to eliminate it is to take it loose from the back of the speedometer and shoot some WD-40 down the inside of the housing.

Mine used to make noise when it was cold, and the needle would jump. However, since I tore mine down...no more noises.

[jbrignac]

Thanks for the tips guys. I'll try shooting the cable down. I've had one of those go bad before and this doesn't sound the same but it's a possibility.

[yuccales]

Cracked flex plate ? Sure hope it's just the speedo cable!

[knomadd]

is there a consistent pattern to the clicking? Maybe faster when you step on the accelerator or slower when you let off? OR is it completely random?

[jbrignac]

It's not the speedo. Still there even with it disconnected. No pattern that I can discern. It always sounds like it's coming from the right side of the dash but can't pinpoint a location. It's not very loud but obvious and enough to be annoying. Where is the flex plate? I should give that a check.

[pat 70/71]

I have the same noise sounds like paper is flapping on something (air coming in the cab) is what it sounds like to me. I'll take a look tomorrow and report back.... cheers, Pat

[ChevLoRay]

The flex plate is the flywheel, when you have an automatic. The torque convertor bolts to the flex plate.

I had a '56 Mercury, back in '65. It had a clanking sound at an idle that was quite noticeable. Those flex plates were different compared to the one these vehicles use. But, I'm still gonna guess that if your has any cracks, it's gonna be louder than a clicking sound, and it won't be on one side.

Make sure your transmission dipstick tube is secure. It's on the right side.

[Stocker]

When my flex plate cracked, it was loud and deep -- it sounded almost like a rod knocking. That's the only one I have heard though, and I suppose they could make different sounds depending on where & how they crack.

[jbrignac]

That can't be it. This thing is really more annoying than loud. It sounds like an electrical circuit popping but I can't find anything on that side that could be doing it. The fact that it seems to move is all the more confusing.

[jbrignac]

So at the risk of sounding like an idiot, I figured out what the noise was. Turns out the screw was loose on my antenna and it shifted just enough that I couldn't see it but it was tapping on the rain gutter and transmitting the noise back down through the antenna into the dash.

[custom1970]

Don't feel bad, if it had been obvious you wouldn't have had to ask everyone-- and i don't think anyone guessed that as the possible problem...
Glad you found out what it was!!