Before we set the distributor in place, we coat the tachometer driven gear liberally with Zip Product's supplied lube. You should apply lube to the distributors driven gear also. Once the Zip Products tachometer driven gear is installed, the distributor should be spun by hand to feel for any rough spots. We had to file the ends of the teeth slightly to eliminate some minor binding we found when we rotated the distributor shaft. If you feel any binding while turning the distributor shaft, gear damage will result. Take the time to check for smooth operation.