My 5 gear of transmission is broken. I know that it is the commom problem for FD. I am wondering that if I don't fix it and keep using the transmission without 5 gear, will it make any more serious problem? Also, when the 5 gear was broken, will it make any sound? because I find some clunk sound, but I don't know where it come from.
Please give me some idea.

 

This happened to me before (snapped the synchro) and I kept driving it and just didnt use 5th gear thinking that it would be alright, but with all the metal floating around my gearbox it found itself jamming up 1st gear as well! So my advice would be don't drive it before you get it fixed. And no it didnt make any noise driving around afterwards.

 

I waited till I could afford the 5th gear repair about 2k miles and didn't use 5th gear unless I rev matched it at highway speed. So I finally got enough for the repair and come to find out the ring did snap in half and metal was floating around the gearbox (the gearbox dont have a filter). So instead of just the 5th gear problem I have the bearings all chewed up. So there is another 200+ dollars in bearing plus labor. Just what happened to me.