Speedometer Cables - things that should be easy but are not

[kopeck]

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

[Mike81K10]

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.

[kopeck]

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

[Mr Diesel]

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.

[kopeck]

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

[bd]

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.

[kopeck]

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