So I'm tooling around in my Vette last evening and I noticed my speedo quit working and I thought "Oh good something else to fix". Anyway my speedo started working again and quit again and off and on. Well my tripmeter hasn't worked in at least 4 years so I might as well look into both issues. So I looked at past threads and found out what a joy it was to change out the speedo and that it takes awhile to get it fixed all the while the car is down. So somebody said just buy another one and replace it while the first one gets fixed. Sounds like a good idea.

So I get on Ebay to find out what a replacement would cost and one ad says I had 1 hour left to get 20% off, $118.00, so I buy it thinking well at least my tripmeter would be working. So I guess my question is does anybody think I really need this speedo to get the MPH to work, now I haven't crawled under the car to see if the cable is any good, I'm just thinking something internal to the speedo is screwed up since the tripmeter wasn't working the next thing to stop working would be the MPH needle. Would that be the sequence of speedo gear failure? Or is it anybody's guess? The car has 91,000 miles

 

Speedo and odo are two different things. Speedo can work fine with a dead odo.

Check cable and tranny gear before fretting over the speedo itself. No sense buying a replacement speedo if you do not need one.

 

Was the odometer working before the speedo indication quit? If yes, the trip meter reset cable may need adjusting or replacement.

Most likely your speedo problems are the cable or drive gear, not the gauge.

 

Yes the odometer was working before the speedo quit, it was just the tripmeter that wasn't counting. Well I guess I just bought a spare speedo that I may not really need. When the Ebay lister said I just had an hour to save $30.00, I thought why not, I've boughten dumber things in my life. But before I replace it I'll definitly look at the drive gear or cable.

Right now I'm looking at a couple of 4 post lifts. After seeing a lot of discussion on the General Topic section I thought this is they way to work on your car. When I decide what I want to do with that I'll start yanking on cables. The Chinese lifts look great for the price, but I'm finding the American lifts aren't that much more and you if look at their sales pitch there's no question. eg Backyard Buddy, Rotary, ect.

 

I chased an intermittent speedometer issue for about a year on my son's 74. The problem turned out to be a worn groove in the small aluminum box that the speedometer cable attaches to at the transmission end (4 speed). The box is attached to the side of the transmission with a small flat metal plate that has a single bolt hole in the end. The plate mates with a groove in the box. The groove was worn allowing the box to shift position and thus the plastic gear would come out of contact with the mating gear inside the transmission. The solution was to make a new plate out of thicker steel such that it was a tight fit in the groove in the side of the box.
I recommend you jack up the car and get under and reach up and see if your adapter box is tight or wobbly as mounted on the transmission. At the same time you can hook up a drill to the speedometer cable at the transmission end and see of the speedometer works.

 

Everything in the speedo is run off the speedo cable, so if there's something not working it's probably internal. All the same, check to make sure the cable is connected at the back (and held by the clip) and connected securely at the tranny. You can put a drill on the tranny end of the cable and see if it works...just check what you can before you pull the dash.

I had my speedo after the trip and odometer both stopped working and the speedo was bouncing like crazy, then just stopped.