Author Topic: Speedometer Cables - things that should be easy but are not  (Read 1051 times)

Offline kopeck

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Morning,

I have a '79 C10 350/Auto with a noise speedometer cable.  My truck has the two-piece (upper and lower) setup. 

I've removed them to measure and get a new set, but I can't find anything that matches.  The lower cable is 23", and the upper cable is 44".

On the upper cable, I can find 41". Short but close that maybe I'm not measuring it the way the factor does.  On the lower cable I can't find anything close to 23".  Also, I'm not sure if they have the right ends.  Some pictures show a male end like I have, some show female, and some show something completely different.

Why is the cable two pieces anyway?  Seems like it just complicates things.

Am I missing something obvious here?

I did remove the drive on the transmission.  The gear was in perfect shape, and the square drive looked good, too.

K




Offline Mike81K10

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Re: Speedometer Cables - things that should be easy but are not
« Reply #1 on: May 06, 2024, 12:55:12 PM »
I believe if your truck has cruise control. I think those that have cruise control has an upper and lower cable. None cruise control I believe has one cable. I will be corrected by someone if I am wrong. I don't have cruise control and only have 1 cable.
"Tell me and I forget. Teach me and I remember. Involve me and I learn." -Benjamin Franklin

Offline kopeck

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Re: Speedometer Cables - things that should be easy but are not
« Reply #2 on: May 06, 2024, 04:21:54 PM »
No cruse on this guy, good old Custom Deluxe.  My Grandfather didn't believe in features.  ;)

I only find one option for upper/lower in my year. 

K
« Last Edit: May 07, 2024, 12:16:46 PM by Captkaos »

Offline Mr Diesel

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Re: Speedometer Cables - things that should be easy but are not
« Reply #3 on: May 06, 2024, 07:46:15 PM »
I have never figured out the rhyme or reason with the two pieces speedometer cables, but based on my experience with these trucks and other GM products from the same time frame I am of the opinion that they were originally designed for GM products that split the cable at the cruise control box. Later GM cruise control product design made the two piece obsolete but it seems they kept using the two piece for some time anyway, presumably to deplete existing stock. Seems like all the common aftermarket  cables are just one piece, unless  you need a two piece for old cruise control.

I also could be wrong about all that and am all ears if someone knows different.
1976 C20 Crewcab, 6.2L/SM465
1982 K30 Crewcab , 427TD/TH400
1983 C30, 6.2L/TH400
1983 K30 Crewcab 454/700R4
1986 K10 350/400. 1989 K30 cab/chassis 454/SM465

Offline kopeck

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Re: Speedometer Cables - things that should be easy but are not
« Reply #4 on: May 07, 2024, 07:15:27 AM »
It sounds like I just need to find a one-piece that is the same length or a bit longer than what I already have, and I don't lose sleep over it.

K

Offline bd

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Re: Speedometer Cables - things that should be easy but are not
« Reply #5 on: May 07, 2024, 08:52:55 AM »
If the only issue is noise, have you considered removing the cables from the housings to clean and lubricate them?  You'll need needle nose pliers, a clean disposable cloth rag, a can of aerosol carburetor cleaner, and lightweight lithium grease.  It might be cheaper than replacing the cables if you already possess most of the materials.  Otherwise, a one-piece cable of the appropriate length is a good solution.  Look for a cable having the same type of termination at the speedometer head as the original.  Some factory cables terminated in a molded square-shank nylon key that engaged the speedometer.  Many aftermarket cables are missing the nylon termination and can introduce a bouncy speedometer needle due to poor fit, so beware.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline kopeck

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Re: Speedometer Cables - things that should be easy but are not
« Reply #6 on: May 07, 2024, 07:09:46 PM »
I cleaned and lubed the top cable, and it made things better, but the bottom one was really making a racket.  I may try it, though, since it really won't cost anything.  It also looks like no one local has one that will fit so I'll need to order, so it could save me some time.

K


Offline philo_beddoe

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Speedometer Cables - things that should be easy but are not
« Reply #7 on: May 21, 2024, 06:55:32 PM »
I have the identical problem and question. In fact, minutes ago after doing a cable search, I posted a question on the length.

A few years ago I did what bd stated and it worked great, but now is noisy again, unhooked it and all is quiet. Mine is also two piece, Id prefer a nice new one piece, my lower is the same as yours, but it seems from my best estimate that its about 60 total. I guess Ill just remove and measure. About $20 for a new cable. Not bad.

This should suffice..

https://www.classicindustries.com/product/1977/chevrolet/truck/parts/6478176.html
« Last Edit: May 21, 2024, 07:02:13 PM by philo_beddoe »
Behold, the day of the LORD cometh, and thy spoil shall be divided in the midst of thee.  Zechariah 14:1

Offline kopeck

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Re: Speedometer Cables - things that should be easy but are not
« Reply #8 on: June 22, 2024, 06:20:25 AM »
Just a follow-up (this spring has been crazy).

Cleaning and re-lubing the cables got rid of the noise.  The needle still flutters around 20MPH (it's done that as long as I've owned the truck, which 20+ years now), and now it does it at 55+ (that's new).  I wonder if my speedometer needs some attention.

That being said just having the racket gone is a huge improvement.  We will see how well it holds up.  If it comes back, I'll just find a one piece cable.

K


Offline Mr Diesel

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Re: Speedometer Cables - things that should be easy but are not
« Reply #9 on: June 22, 2024, 08:00:26 AM »
Probably need a new one to completely get rid of the flutter. All it takes is one tiny spot snagging inside on a kink, bend, or cable strand frayed. It is also critical that you don't kink the new one putting it in.
1976 C20 Crewcab, 6.2L/SM465
1982 K30 Crewcab , 427TD/TH400
1983 C30, 6.2L/TH400
1983 K30 Crewcab 454/700R4
1986 K10 350/400. 1989 K30 cab/chassis 454/SM465