1985 Silverado speedometer cable problems

[Texas Agman]

My real nice '85 Silverado has 230,000 miles on it and the speedo cable keeps coming apart according to my local rural mechanic. I was told a couple of times that the cable is in two sections and that they separate, rendering the speedometer useless. I checked most of my usual supply houses for parts without success. Have any of you had speedo issues with cables and the parts necessary to change the speedo readings when the rear axle ratio was changed ? This is a first for me and I don't have a clue what I am talking about. Thanks for pointing me in the right direction.

[Tiger Joe]

what kind of setup in your 85, 2wd or 4x4, auto or manual? they list a bunch of different cables depending on the setup.

LMC truck lists prob close to 5 or 6 cables for a 1985.

Also they do match little ratio adapter boxes to adjust if you change the rear axle, what swap did you do?

[hatzie]

The drive and driven gears can be changed fairly easily. Usually, but not always, you don't need the ratio adapter.
Roughly ten or a few more pages of 1985 speedometer gear charts can be found in the 1985-1991 GM Light Truck parts books starting on page 4-117.
Download them from the manuals post in my signature... or read them Online here http://gmpartswiki.com/getpage?pageid=58504
You'll need the tire size and axle ratio along with the transmission or transfer case type.

[Texas Agman]

Originally Posted by Tiger Joe

what kind of setup in your 85, 2wd or 4x4, auto or manual? they list a bunch of different cables depending on the setup.

LMC truck lists prob close to 5 or 6 cables for a 1985.

Also they do match little ratio adapter boxes to adjust if you change the rear axle, what swap did you do?

.

My 85 is a 2x2 with a 700R automatic. I went from an original 3.08 to a 3.73 rear gear for pulling purposes here at the ranch.

LMC is one of the supply houses that I did not check with, so thanks, Tiger Joe.

[Texas Agman]

Originally Posted by hatzie

The drive and driven gears can be changed fairly easily. Usually, but not always, you don't need the ratio adapter.
Roughly ten or a few more pages of 1985 speedometer gear charts can be found in the 1985-1991 GM Light Truck parts books starting on page 4-117.
Download them from the manuals post in my signature... or read them Online here http://gmpartswiki.com/getpage?pageid=58504
You'll need the tire size and axle ratio along with the transmission or transfer case type.

Thanks, Hatzie. I will pass on all of this information to my mechanic out here in the boonies. Our nearest city shop is 75-100 miles away. Really appreciate your valuable input on the issue.

[Tiger Joe]

LMC lists both the upper and lower for your truck

Advance auto lists upper and lower as well:
ATP cable- Y-814 upper
Y-808- lower
if advance's website is correct