Speedometer and Odometer quit

[Fjordlander]

Hello all,

The speedometer in my 76 Scottsdale K10 has never worked correctly even after replacing the cable but the odometer was always accurate. Recently the odometer quit working and the speedometer (which used to just bounce around) doesn't move at all. Am I correct in assuming there's something wrong with the gears that the cable connects to?
If so, is this an easy thing to fix? I'm learning as I go here and have no idea whats involved in this lol

 

[Rickf]

Does it have factory cruise control?
Most likely the plastic gear at the transmission is stripped OR the cable is broken. You could disconnect the cable from the trans and spin it with a drill, if the needle moves it's a gear problem.

 

[KnuckleBuster]

If the cable is intact, the next place to go is the driven gear in the transmission. Very easy to remove and inspect. Might also make sure that it is the correct one. Years ago I had one that the speedo bounced a lot in. The gear looked ok but turned out to be the wrong one.

 

[idahovette]

OK OP has a 76 K10, if it IS a 4wd, the gear is in the transfer case and I'm betting it's a metal gear. Not saying it couldn't be bad but unlikely. May have a ratio adapter that may be bad or the key is twisted? Could be a bad cable, check it like @Rickf suggested. Work your way up, maybe the speedo head just quit?

 

[Fjordlander]

Does it have factory cruise control?
Most likely the plastic gear at the transmission is stripped OR the cable is broken. You could disconnect the cable from the trans and spin it with a drill, if the needle moves it's a gear problem.

No cruise control. I'll trying spinning the cable with a drill this afternoon and see if the needle moves

 

[Fjordlander]

OK OP has a 76 K10, if it IS a 4wd, the gear is in the transfer case and I'm betting it's a metal gear. Not saying it couldn't be bad but unlikely. May have a ratio adapter that may be bad or the key is twisted? Could be a bad cable, check it like @Rickf suggested. Work your way up, maybe the speedo head just quit?

Yes, it's 4wd. I'll test out the cable and then inspect the speedometer gauge itself

 

[Ricko1966]

He has/had 2 problems if Odometer worked but no speedo that is in the speedometer head itself. The same cable,transmission gears etc. Drive the speedo and odo at the same time same spot. So speedo may have died first then a cable,transmission gear or odometer followed. Pull the cable at the transmission end,spin it with a drill. Does the odometer work? Yes?. It's in the transmission. No. pull the cable from the speedometer is it spinning, yes speedometer needs repair. No.? its a cable or cruise control transducer.

 

[Fjordlander]

He has/had 2 problems if Odometer worked but no speedo that is in the speedometer head itself. The same cable,transmission gears etc. Drive the speedo and odo at the same time same spot. So speedo may have died first then a cable,transmission gear or odometer followed. Pull the cable at the transmission end,spin it with a drill. Does the odometer work? Yes?. It's in the transmission. No. pull the cable from the speedometer is it spinning, yes speedometer needs repair. No.? its a cable or cruise control transducer.

I pulled the cable and spun it with my drill and the odometer and speedometer both work. So it's not the gauges or the cable and there's no cruise control.
Based on what you said, it's the transmission. Is this a difficult repair? I'm learning as I go here

 

[Fjordlander]

I ordered new gears but I evidently got the wrong parts. My truck doesn't seem to use the bullet speedometer like other vehicles of this era. Can someone look at these photos and tell me what the part is called I need to order?

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[idahovette]

The drive key is broken off in the transfer case gear????? Maybe all you need is the drive key??....and to get the broken part out