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Discussion Starter · #1 ·
I checked the archives, but I couldn't find anything very specific for my question, so here it goes.

OK, I'm dumbfounded.

I have never seen my car do anything like this before. I was cruising along, at the healthy legal speed of 70mph, and out of no where, my speedo just wraps all the way back to 0. It worked perfectly, up until then. I wasn't accelerating, I wasn't decelarating, I was just cruising. So, now my car's odometer has stopped working, also. I left the car in the driveway, since I don't want to wrack up "non-documented" miles, but I have got to go to school tommorow.

Any ideas? Where does this thing connect to the tranny? Can I check it by jacking the car up? If it's not the connection to the tranny, has the cable maybe broken?

There is a local junkyard, that has the 140, or maybe 120 mile an hour speedo, from a '79, so what would I have to do to recalibrate this one, if I can't fix my own?

Any help is much appreciated.

Chris Behney
President
Redline Autosports
 

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Replace your cable

Sounds like you broke your cable. You can verify this, if you disconnect the cable from the back of the speedo, and try and pull out the cable. If you can pull the cable, then it's broken, if not, the cable is still in one piece. A faulty speedo usually starts 'bouncing' around before it quits. Since yours suddenly went dead, the cable is the more likely culprit.

FYI, I've replaced mine, since the cable wrap was frayed in the engine commpartment, and the cable became rusted, and broke. No problems since replacing it. Very easy job, just need a little manual dexterity to get it done.

Dave
 

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Replacing your cable

The cable connects to the tranny just behind the right side tranny mounts. I just took mine out the other night and I still have cramps in my hand from working under the dash reconnecting it. I thought mine had broke but it didn't, I replaced the 4 spd with a 5 spd and I think the p/o of the 5 speed swapped speedo cogs because it (the cog) ingages when I push it in past the keyway, But not when put in correctly. Now I have to find one that fits right..
 

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RE: Replacing your cable

A preventive maintenance tip: speedometer cables, particularly old ones, need lubrication and corrosion protection. A moly lube works best, and we sell a good one called Dri-Slide. We're going to have a paid ad on this forum soon so that Derek can make some money. In the meantime, check out our website at www.russack.com for detailed product info. Price is $7.95 plus $3.95 S&H for a bottle and applicator needle.
 

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<b>RE: Replacing your cable</b>

I read on one of the web pages that the speedo cog was the only diff. on the z's, depending on the diff. so I would "Think" the other speedo would work. Just my guess though.
 

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Cogs and housing

Yes the cogs need to stay with differential, The housing must stay with the tranny. It's pretty easy to change out the cog.
 
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