overnight on my '85 GSL. I was looking under the dash for any big sign with an arrow that would say "over here! here's the problem!" pointing to a loose connection that would make it easy to fix the problem. No luck though. Any suggestions on what/where to check or is it a waste of time and should I just not bother?

Cable broke or pulled out of the back of the speedo. I know the cable doesn't clip into the back of my speedo that well.

thanks for the tip. I'm going to go check it out - hope i can find it! do I need to remove anything to get to it?

man if you dont have to dont remove the instrument cluster,,,its a bitch,,,have someone attempt to turn the speedo cable from under the car, u should see some slight movement on the odometer,,if not, than most likely the cable is broke or has come loose from behind the cluster,,,but if it does move, than its either not secure in the transmission or the gears have stripped,,,my cable has a little foot on the transmission end of cable, if its broke off that will keep it from registering on the speedometer,,,good luck,,,

well, as it turns out. didn't have to remove it, but was able to see what you mean - it is a bitch. But the cable was loose on the other end - under the car. I was driving around this morning and heard something dragging under the car... by luck as it is a rare coincidence that i'm cruising at idle speed and have my stereo turned off at the same time. Thanks for the pointers. It's all good and working now.