speedometer advice

[rcm1958]

I have a '67 C-10, purchased 6 weeks ago that could be termed tired but trustworthy. It runs well, the lights, turn signals, wipers and brake lights work. My instrument cluster, however, does not work (except for a generator light that keeps coming on/off). Not having a gas gauge is fun as is not having a working speedometer! Last week I replaced the VERY rusty speedo cable with no positive results.

Where do I go next?? Anyone out there want to pitch some advice??

RCM

[bonnieclyde100]

i would take the speedometer out and check it by taking a drill and put it up to where the cable hooks up and run drill in reverse and if the speedometer doesnt move then it it bad. if it does move then the speedo gears in the tranny are bad.

[Stocker]

^^ Good advice. A quicker, easier 'first check' would be to remove the speedo cable from the trans and connect your VSR drill motor to that end (with the other end still connected to the speedo head). If that works, you won't have to go to the trouble of removing the speedo head -- just replace the gear at the trans.

[Ol Blue K20]

Originally Posted by Stocker

^^ Good advice. A quicker, easier 'first check' would be to remove the speedo cable from the trans and connect your VSR drill motor to that end (with the other end still connected to the speedo head). If that works, you won't have to go to the trouble of removing the speedo head -- just replace the gear at the trans.

I like this, nice and easy

[68gmsee]

Also make sure the connector is in all the way and not crossthreaded behind the speedometer.

Re. gauge cluster problems: Check the big connector for damaged lands and check the ground clip on the back of it. Insure you have good grounds on the cab to the engine and engine back to neg post on battery.

May even be a good time to add grounds form cab, radiator support and bed to frame and one from engine to frame. All these components relied on bolts that have corroded over the years for grounding.

[AirSpeed]

My 69 had the same problem, mine turned out to be the plastic piece in the tranny, it was no longer square. I still haven't fixed it so I use the tach to gauge my speed. I got pulled over for speeding once and told the cop I was using my tach, he volunteered to drive in front of me at 25, 36, 55 and 65 so I could take note of the rpms at speeds, the rpms I guessed were 10 mph high. Thought for sure he would give me a fix it ticket but he didn't, he said the tach was fine. I may never fix it!
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[jocko]

if it turns out you need the tranny speedo gears, here is a good resource:
http://www.transmissioncenter.net/sp...#Misc.%20Gears