Hey everyone. Here's the scoop. I'm driving a '90 Honda Civic Hatchback Dx, manual, 1.6 dohc B16.

About a month or two ago, third gear started grinding in high rpms. I understand this is somewhat of a common problem. I've visited other forums and seen various recommendations. I just got the chance to try out one of those recommendations, but let me first say this. Recently, the grinding issue has gotten a little worse. It grinds into second and sometimes fourth. There isn't really a strip long enough for me to know if it would do it into fifth, but I'm assuming it will. I spoke with a mechanic and he suggested the synchros were getting worn out and that this is a common issue. He - just like many forums out there - suggested replacing the fluid with synchromesh.

I replaced the fluid last night with Penzoil Synchromesh, then tested it last night. The mechanic suggested that it might not take into affect immediately. My question is this: how long (if this is to fix it at all) will it take for the grinding to go away? I just tested it this morning and changing gears at low rpms actually feels much smoother, but still, high rpms results in gear grinding.

I came across a forum where someone suggested taking the car out for a 100+ mile ride where little shifting would be required. Basically, what I'm trying to say is that I've seen a handful of advice, but no definitive answer. So, should the fluid switch fix my issue, and if so, how long should i expect until this grinding goes away? If it doesn't, are the synchros definitely shot; if so, would a new tranny be cheaper then getting this one rebuilt? Any help would be appreciated. Thanks!

 

Honda transmissions use 10w-30 motor oil, so putting in anything else isn't going to magically make your problems go away. From what I can tell, it sounds like your grinding problem has gotten pretty bad, so something that simple probably isn't going to fix it. I would look into just replacing the tranny with a used Japanese one, since it'll end up costing next to nothing (if you can do the labor) and will prevent you from having to experiment with various "quick-fixes," or something much more expensive and ultimately pointless like a transmission rebuild. A used, low-mileage 4G tranny can be had for under $200.

 

That cheap eh? Any recommendations as to where I should look to purchase one? I understand ebay is a good place to find inexpensive parts, but I'm a little leery to go there for a part that the seller claims works, but ends up not quite cutting it.

I was thinking about it today and I do feel that replacing the tranny is going to be the best option. Gear-shifting feels pretty smooth now, but of course this is just low rpms; however, nobody really needs to be driving like a bat outa hell anyways; so i think I could go for a good bit longer without actually needing to replace the transmission as long as I baby it. It probably wouldn't be until this summer that I could afford any more then $200 for a transmission. But anyways, like I said, any recommendations for where I should start looking? Thanks for the advice so far.

 

Check ebay. See if you can get a trans with a factory limited slip differential. Im pretty sure the JDM Trannys all come with an LSD. Its definetly worth it. Oh and if you get a used trans it will be fairly easy to do the labor, as your be taking the crap one off and just replacing it with the newer one. Id say its definetly a Do it yourself type of job.