So every now and then I get grinding when upshifting from 1st to 2nd. And sometimes I have the same grinding (milder though) in 1st when the car is starting to move from rest. Usually the grinding is not noticeable but every couple of months the grinding gets violent for a day or two (~10-20 kms of city driving) and then goes away (I usually just ride my clutch for those couple of kilometers). Also when I have the problem upshifting at higher RPMs reduces the grinding.

My guess is that the problem comes from the 1st and second synchromesh. Though I don't exactly understand why the problem is not consistent.

Note that I feel like the problem happens when I have more people in the car (maybe because I'm conveying more torque?)

I thought I'd do a tranny fluid change first. Though I doubt it'll solve the problem since the grinding does not happen in all gears.

On another note, I've heard that for synchro issues and notchy trannies a "band aid" solution that works wonders for a long time is the GM synchromesh modified friction tranny fluid. I'm not a fan of using non-honda fluids, but there are people that swear by it on the Honda forums. There was even a guy that ran the GM MF in his S2000 for a very long time and was very happy with it.

So any thoughts on what the issue might be?
- 7th gen Honda Civic lx (05). Obviously with a manual tranny!

 

Sounds like you need a 1-2 sleeve set. Let me know if I can help you further

thanks