I have a ls transmission all gears go in without any grinds only problem that im having is that shifting from 1st to 2nd. 2nd gear grinds and doesn't engage when i let off the clutch happens randomly not all the time what could this be ??

 

2nd sleeve assembly. That includes CS 2nd gear, 2nd gear synchro and spring, 1/2 hub, 1/2 slider. As a bonus you'll also get a new 1st synchro and spring.