speedometer not working
 

I have a 81 c10 with a 72 350 engine. Has a th350 automatics transmission w-cruise control. Speedometer has not been for about 6 months. It stays steady below zero and once in a while it bounces when road is bumps. It has two speedometer cables.

Best way to diagnose. I read other posts on the subject but am still confused. When using a drill to check if speedometer turns, do I use the drill on the inlet that goes directly into transmission. I still have speedometer cable attached to truck so I do not how difficult it is to remove but looks easy.


Thanks , on my last matter I finally replaced temp gauge with mechanical and truck is running fine, the old gauge was off by 35 degrees. Thanks for the help.

Re: speedometer not working
 

Truck has two speedometer cables. I was wondering what is the best way to check cable that attaches to back of gauge ( hoping I don't have to take off gauge cluster. Also, when putting my head near the brake, I found the speedometer cable, but could not see where it connected to gauge . I might take another look. If I decide to take gauge panel off, is there any tips to safely do it, and how much give will dash have so I don't pull any wires out. Current symptoms speedometer does not move only when driving under bumps and odometer does not work, odometer takes about a month to register a mile.

I am new at this and only with dash is taking it off to replace wiper switch.

Re: speedometer not working
 

Easiest way is with a drill and a buddy. Disconnect the upper cable at the box on the fender. Hook up the drill to that. if that works, then get your buddy to crawl under the truck and disconnect at the transmission. Hook up drill again. I would think that the lower cable or the box would be my first suspects.

Re: speedometer not working
 

I was checking how easy it was to remove cable end from the fender side, then I immediately retightened. When driving today it was working. Hopefully, it was just loose or the line was really finicky because it is working now. If it holds up that sure would be an easy fix.Thanks for help mrold88.

Justin