Last year I busted the keys on the 5-6 synchro during a power shift, so as an experiment I decided to rebuild the syncrhos myself. Having never opened a transmission before, never seen inside one, and with nobody guiding me I figured it was a write off but a fun exercise anyway. I put new carbon fiber blocker rings in all the synchros, new keys, springs, flipped the reverse synchro around (as its dog teeth were all bashed and it would always kick out of gear), steel 3-4 shift fork, and put in a new 5-6 synchro assembly. To my dismay the transmission works. Reverse works (and never has since I owned the car), 5th works... the only problem is that I get gear noise/whine when I'm in 5th or 6th.

Honestly, I couldn't care less, I drive enough cars with straight cut gears that it's all white noise to me now... but, is it hurting anything? After all, these aren't straight cut gears. I never bothered to check any of the clearances because I figured all the new parts I put in shouldn't affect anything since they're really just floating on the shift forks.

Is this just some break-in noise or should I stop driving it?