Speedocable problems

[Frijolito1988]

hey guys need some help.

I have a 72 GMC 2500 The speedo does not mark at any speed. I took off the speedo cable and it is not knicked, broken , and moves freely and good.

I hooked up 1 end to the speedo and the other end to a drill, put the drill in reverse and the speedo moves like its supposed to and also the mileage. When i put the drill going " forward " or clock wise the needle just fumbles around not going over 20 MPH.


If my speedo cable is good and not broken, and the gauge looks to be in good working condition , Should i be looking to replace the speedocable housing in the tranny ? or am i missing something ? It is a 402/400 combo.

Thanks in advance.