I have a question regarding the synchronizers on my 3 speed trans but this question can apply to 4 speeds also. I'm rebuilding my trans using all NOS GM synchronizers, gears and blocking rings, all in perfect condition. The 1st and reverse synchronizer slides very nicely but the 2nd and 3rd less smoothly. The GM shop manual says that the synchronizer assembly (hub and slider) is a matched set and must be kept together. No problem, I haven't mixed them up. My question is, is the circular location of the slider on the hub matched also? If so, then there's probably a mismatch there as I've removed the slider from the hub without marking the relationship. Is it just a question of trying out the slider on each of the 30 different splines on the hub to find the smoothest combination. Or are there other ways to ensure a smooth sliding action. All comments and suggestions are appreciated. Sorry about the long-winded question, but I want to get this right the first time. Thanks for any help provided.