I have had the C clip rings from the newer style transmissions pop off on me a few times. The shift forks are not all held in by roll pins now, but rather C clips... Nissan says to replace them Every time after they are removed and I highly Agree with them. I have had them pop off, and have it stuck in say 4th gear, and the C clip gets stuck and Jams the shift assembly and you cant go in and or out of gear.