need insight.. 2nd GEAR started POPPING OUT..d16Z6/HYDRO.. any suggests?

 

Never heard of that motor, but in any event the transmission needs to come out and get pulled apart most likely. D series trans can have the countershaft bearing walk out of the case and cause this. Or a pile of other possible issues that nobody can see from here.

 

if its a D16z6, pound the ISB back down and stake it.

 

Ditto the above, I would also check shift "linkage" make sure #13 and #14 are not bent.

Make sure #14, Extention Change Rod is functioning properly, make sure #s 10, 18, 19, and 26 are there and working as they are supposed to, the same goes for #s 15, 16, 17 and 30 at the other end, in fact make sure anything to do with the shifter is there and working properly and not worn out...
http://www.acuraautomotiveparts.org/...ystemcomp=List All&vinnoT=&trim=&trans=&view=normal

If all the above is in good working order, you will, as mentioned, have to pull the transmission and open it up, I would check the shift forks and shafts, they can be worn out or bent...
http://www.acuraautomotiveparts.org/...ystemcomp=List All&vinnoT=&trim=&trans=&view=normal 94