I have a 1991 civic si with the jdm b16a and y1 cable non-lsd transmission. I drove this car almost 4k miles after the swap and now it will not stay in 5th gear for longer than 10 seconds or so. It seems to grind going into 2nd and 3rd all to easy also. I do a whole lot of driving at 80mph so i need it to stay in 5th gear! So am I looking at a trans rebuild or what?