I have a 1985 S10 Blazer and the speed cable was not connect at all when I bought the truck. The cluster was not hook up completely. They claim it a new cable but did not fix the problem. The speed thing would go around and around and you never knew how fast you are going. Some of the other gauges were faultly as well. I was told it was the cluster is faulty.
So yesterday, I finally found one complete at a junk yard after a few months of looking for one. I took out the old one and re- hook up the one I just got from the junk yard. All the gauges are showing they all work!
Sweet!!
BUT, I havn't taken it for a test ride yet, and I notice after when I hook up the speedcable and started the truck up, it was sittinf down below the starting point. (under 5mph)
Will this correct it self after I take if for a ride? I was told that there wasn't any special I needed to do other than make sure there was grease (lube the cable)
I hope I didn't miss anything? and not sure if it ok to take for a test ride, don't want to mess this one up.
Help!

 

I've been curious about this myself mine also goes below the 5mph mark but mine is off speed wise and it wobbles sometimes while driving.