Speedo reads slow and bounces

[Stew_Magoo]

My speedometer bounces at low speed, it reads slow, and I've never seen it indicate over 45MPH. While I had the instrument cluster apart for new bulbs and a cleaning, I spun the speedo with my drill and it would bury itself and acted like it had no issues being spun by the drill. Anybody had this issue? Any tips where to start looking for a solution?


Truck is a 1990 V3500 with a TH400 and a NP205.


Thanks.

[bowtiemanchevyman]

sound like your cable or the gear in the tranny is going bad. it is ether the end of the gear is worn out and not able to turn the cable, or the cable is just gone bad. un hook the cable from the tranny and look and pull the cover off the gear and pull it out look at the end if it is not square any more u need a new gear. you can check this by hooking up your drill to the cable at the tranny end and see if it woork and you turn the drill on and off.