I installed a new cable on my 77 long box stepside with 350 trans, and it's not the speedo, I think. At least I disconnected the cable at the back of the speedo housing, and the shaft doesn't turn while going down the road. Must be a bad gear in the tranny?!? I dunno, never took one apart. Waddya think, Chuck? Any help would be appreciated.<p>BTW, excellent posts about signal problems. I am going to try hunting down my bad ground tomorrow. I'll let you know what I find.<p>My truck is a continuous project. Next is Power steering hoses (leak like a seive), so they leak on my pristine concrete driveway; then door hinge bushings and pins, then new cab mount bushings, then rebuilt heads and a new manifold.