why does my speedo not work?

[ncgamedog]

the speedo in my 85 siverado isnt working. it's a LWB 4x w/ a 305, 700r4, and full time 208 w/ slip yoke. the cable appears to be hooked up but the truck is equiped w/ cruise would this make a difference? i cant think of why else it wouldnt work doesnt look like the dash has ever been out of the truck. where should i start? thanks- justin

 

[dyeager535]

Does cruise work? I suppose it's possible that cruise could still work without the speedometer, if ONLY the speedometer was messed up. VSS handles cruise speed, so if the cable is turning up to the speedometer, cruise should work. As in the other thread about speedometer not working, you'd have to know if cruise was working before the speedometer quit.

Next would be to disconnect the cable at the t-case, and spin the actual cable end with a drill. If the speedo works, then your problem is with the drive and/or driven gears in the t-case. If not, then it may just be disconnected from the speedometer behind the cluster.