2006 Civic With Possibly Bad Synchros?

Messages
9
Location
Chicago
Hi all, long time listener, first time caller. I have a 2006 Civic with about 70,000 miles and and manual transmission. Today, while in neutral and traveling at about 10 mph I revved the engine a little bit to engage 2nd gear. When I gave it gas I heard a slight "grinding" sound that sounded like about 5 gear teeth clacking. I drove around a little more to investigate and I found that when in neutral and traveling between 5 and 10 mph I get this grinding noise intermittently and it varies between 1 and 5 gear teeth clacking. I get the clacking very occasionally when I'm stopped and rev the engine, and never get it above 12 mph or so or when the car is in gear. The transmission still shifts very smoothly and does not grind into gear like transmissions usually do when the synchros are going. Any ideas?
 
Messages
22,188
Location
Colorado Springs
If the noise doesn't occur when shifting, I doubt it's the synchros. Could be something in the transmission or the clutch itself like a broken pressure plate perhaps, or a bearing in the trans going bad.
 
Messages
17,301
Location
OH
More likely a clutch release problem than the synchros. No knock on you, but it would be hard for even the most ham-fisted driver to ruin the synchros in 70K. Is the clutch hydraulic or cable? If hydraulic, I'd try a good bleed and see what happens.
 
Messages
5,628
Location
London, ON, Canada
I would also try a drain and fill with fresh MTF. Hondas from what I have seen seem relatively hard on MTF (degradation in shift quality happens earlier than some other makes) I put Pennzoil Synchromesh in my SI and I love it, it has been working wonderfully for the last year... Buttery shifts.
 

BrewCity

Thread starter
Messages
9
Location
Chicago
I did a drain and fill with Honda MTF about 10 months ago ... too bad there's not an easy way to check the fluid level! It's a hydraulic clutch and probably has 8 year-old brake fluid in there ... I'll have to look into bleeding it.
 
Messages
680
Location
Hawaii
Sounds like a clutch problem. How high or low is the bite point? If it's really low, you may need to bleed your hydraulic clutch. As a habit, I normally don't like hovering in neutral too long when the car is moving.
 
Messages
2,352
Location
Texas
Originally Posted By: BrewCity
I did a drain and fill with Honda MTF about 10 months ago ... too bad there's not an easy way to check the fluid level! It's a hydraulic clutch and probably has 8 year-old brake fluid in there ... I'll have to look into bleeding it.
You need to flush that 8yo fluid out of there first, and then bleed it. That will likely solve your problem. Let us know. If you have 8yo fluid in your braking system as well, that also needs to be flushed out. Honda's recommended change interval is 36 months or 36000 miles for both of these. You are WAY past due!
 
Last edited:
Top