Finnally found a obd-1 (or w/e its called) computer to check for codes. It says the speed sensor is bad. The speed thing attached to the ecm has already been replaced and didnt fix it(got it for free wooohoo)..I havent replaced the sensor on the tail of the transmission yet. I noticed when i turn the steering wheel the check gauges light flickers and i hear a buzzing etc. coming from somewhere behind the cluster. No idea where yet. Anyone had similiar problems? I bought the blazer this way thinking it would be a "easy" fix..ugh..

All the gauges work but the speedo.

91 s10 blazer 4.3 tbi

 

im pretty sure that the gear in the transmission is shot or the connector in the back of the cluster is worn or disconnected. if its an analog cluster. if its digital i have no clue.

 

This truck will have an electronic VSS. I would remove the VSS, inspect it, clean it and the toothed ring inside the transmission tail housing. Reassemble and see if anything changed. If not, I would replace the VSS.