Mervic

I need help on my tranny. I replaced the CV boot on the passenger side. After I replaced everything I noticed that when I downshift to second it will make noise like a grinding sound. It only does it going to second gear, not in any other gear. Upshifting to second is OK though. I dont think it is anything to do with replacing the CV boot. Maybe it was just a coincidence that the second gear synchro starts to fail. Anybody??