So I just installed a 5 speed transmission in my 78 280Z. Used to have a 4 speed. Before installation, nothing was wrong with the clutch, and I did not think I needed to replace it at the time. It was strong and never slipped. I did not remove the clutch and it seemed to be in good condition as far as I could tell on the flywheel.   While test driving after the install, I notice that it seems like the clutch slips a bit at 3 & 4 gear shifts. The question would be is this a sure clutch going