I found a instrument cluster for my 66 Fleetside and I need some advice. I've had speedometer problems for a while. When I replaced the tranny I got a new cable from Chevy Duty. When I took the cluster out the tip of the cable was broken. I kept the old cable and it seem to turn ok. My question is this, the speedometer I took out spins very easily and the dial sort of bounces (that's actually what it did while installed until it totally died). The replacement speedo unit gives a good bit of resistance when I turn it. I assume the one with the resistance is more likely to be good?