70 LT1 - Can you help ID this whistle/ chirping noise?

[David S.]

Re: 70 LT1 - Can you help ID this whistle/ chirping noise?

Circling back here. Finally figured out the noise.... It was a bad speedo cable. The cable was vibrating inside the plastic casing and making a terrible whistle noise. Oddly enough the speedo still worked. Once disconnected from the trans and zip tied the noise went away complete. New one is on order.

Go figure, yanked out the heater box, blocked off all the holes, bypassed the core (obviously) all before figuring out it was the cable.

Best,
Dave

[Paul D.]

Re: 70 LT1 - Can you help ID this whistle/ chirping noise?

Have you tried cleaning and lubricating the cable inside the housing? Important to clean the cable with solvent to remove old and sticky lubricant before lubricating the LOWER 1/3 to 1/2 of the cable. I usually use GM Lubriplate from my at least 40 year old can, but have used other white lithium type grease. I suggest this because I have heard several tales of disappointment with replacement cable assemblies. Also, replacing the cable assembly is not a real easy job. Might be worth a try. Chip.

[Mark E.]

Re: 70 LT1 - Can you help ID this whistle/ chirping noise?

How is this done?

[Paul D.]

Re: 70 LT1 - Can you help ID this whistle/ chirping noise?

Well, the hard part is getting access to the end of the cable at the speedometer head. You may be able to work your hand up to it from below without taking much apart, or you may just prefer to pull out the left hand lower dash. The cable is secured to the speedo with a spring clip. Hard to explain, but if you get your hand to it, wrap your fingers around the cable and with one finger push up on the spring clip and then pull back on the cable to release it. Once you get the end of the cable down to where you can get to it, take some needle nose pliers and pull out the small cable. It may not come out real easy if the old lube has gotten sticky. After you pull it out about 1/2 inch, you can then spin the cable and that may help. Don't get too agressive with the pulling as you don't want to pull the end off the cable. If you do, you can get replacement cable to put back in your old housing. If someone could post a photo of the cable connection at the speedo, it would really help you understand how to disconnect it. Going back is much easier as it just slides back on. Chip.

[David S.]

Re: 70 LT1 - Can you help ID this whistle/ chirping noise?

Have you tried cleaning and lubricating the cable inside the housing? Important to clean the cable with solvent to remove old and sticky lubricant before lubricating the LOWER 1/3 to 1/2 of the cable. I usually use GM Lubriplate from my at least 40 year old can, but have used other white lithium type grease. I suggest this because I have heard several tales of disappointment with replacement cable assemblies. Also, replacing the cable assembly is not a real easy job. Might be worth a try. Chip.

Given the condition of the cable I'll run the risk of a replacement. Thanks for the info though.

best,
Dave

[Mark E.]

Re: 70 LT1 - Can you help ID this whistle/ chirping noise?

Thanks Paul.