Well my not happyness made it back to Shaftmasters, and yes I worked with them, they are great to work with, I purchase two drive lines from them, they refunded my money on the first no problem, the second one still vibrates, so I take it one of you guys are a plant...... the OP ask for my opinion and I gave it, I'm glad for the people that have not had problems, but I have and still do, just one of those mods I wouldn't do again, wether it be a Shaftmaster or any of the other single piece alum. drive line manufactures, how many of you have step gears (4.10 or better) and no vibs?