OK folks, I just bought a new speedometer gear for my Jeep, took off the old one, put on the new, plugged her back in, hooked up the sensor, went for a test drive, and apparently I was goin 0 mph when I was goin about 55.  Any ideas what might be the problem here?  I'd like some help ASAP so I can fix it before the time I WOULD LIKE to go to bed tonight.  Thanks.