engifineer

Mine does not pop out, just grinds when shifting fast at high RPM. Synchros are likely shot. Babying it till winter and will try to deal with it then. Fine on lower rpm shifts if I dont bang it through the gears but on track, it is coming up more and more. Slave is good, good hydraulics, new clutch, etc. So .. time to tear in or buy a used one. And likely both. Find a good used one for the interim, tear down the other so I have more time with it to decide what I do next. If the gears are damaged then it is toast, gears are unobtanium other than I think maybe 1st and 6th. There simply are no more new replacements for the others.

Bullwings

I also have the 3-4 grind under hard load shifting in vtec (down shift 5-4 is fine). It's been like that for 3+ yrs now. I switched to Amsoil MTF for the majority of my fill, and do half a quart of the OEM Honda MTF. It helps, but you also need to give your transmission more warm up time driving it first thing in the morning.

I recently did tried doing the debur fix talked about in this thread - https://www.s2ki.com/forums/s2000-un...1219686/page2/ - after draining my transmission fluid - let it sit draining over night.

Essentially rowing through the gears a few hundred times without using the clutch and no oil in the transmission (car off - obviously). Seeming felt better during a street drive, but the real test will be at the next track day.

engifineer

On mine I am pretty sure the synchros are just plain worn out. I have not tried the empty the trans and row the through the gears thing yet and may but it has progressed slowly each track day for a while. Now it is a lot harder to avoid the grind unless shifting at low RPM. I may have a handle on a fairly priced unit with 98,000 miles on it. If I jump on that, I will at least have a spare I can tear down and not be rushed on to see what I do next with it (or at worst 2 of them I can choose the best parts from). Being a track car this is not a bad thing. I just tried to check in on a 7,000 mile transmission ... but they want $3,500 for it I mean it is practically brand new but damn ...

Dibsen

My car lived a very gentle life before I got my hands on it. I noticed my gearbox not liking high revving track abuse while at RA and Daytona. I’ve watched a few videos recently and the driver was commenting on the same grind.

im sure my shifting is a little sloppy but it seems like this trans doesn’t like being man handled.

Bullwings

My transmission, motor, differential, and clutch are all original with over 100 track days on them. I don't skip shift. I heel-toe rev match and engage every gear, not just row through it without releasing the clutch.

Anyway, i'm on borrowed time. Just waiting for one of the four above to fail. Have a full OEM clutch kit with AP1 fly wheel ready to go in. If differential goes, i get a 1.5w LSD from Kaaz or OS-Giken.

Motor or transmission - i'll go visit Formula-S and throw money at them. They'll make it better. LOL

engifineer

My diff as far as I know was original. Between the 2 previous owners and me it saw a lot of hard launches autocrossing. It failed on me last year on track, but more likely due to previous launching and less from actual track use. So the spare diff is in now and the original is sitting on my shelf. Planned to send it off for puddymod and an OSG setup but have not done so yet.

Trans is original.

I replaced the clutch after I bought it (a bit over 100,000 miles) but then again at 160ish thousand miles. But it was not worn out this last time. Friction material started coming apart and caused it to fail early. Not sure why that happened. It was a Honda Clutch direct from Honda. Was perfect before that happened and crazy as it is, did not even slip when it fell apart with 50% of the material falling off. It just started binding up and not disengaging during a track day.

So kinda sucks to pull the trans again but that is what I gotta do! I replaced my clutch last year, then helped my friend do his, so getting plenty of practice pulling the transmission out .

Dibsen

I was kind of shocked how nice my disc looked when I pulled it at 130k miles, it was so good I kept it. Like I said though, gentle life.

I intentionally avoid hard launches during autoX, the 1/1000 of a sec difference isn’t worth it to me. I have plenty of other places to pick up speed.

i really only use autoX as a test and tune. I love dialing this car in. I would like to get more competitive on track but I am looking at a race prep’d Rx7. I don’t really want to turn the S into a dedicated track machine.

although I wouldn’t mind getting a rough one. Mine is just too clean to cut up.

engifineer

I enjoy it too much not to use it for a track car But I bought it originally to be an autox and track car. A lot of autocross courses are designed to not reward a hard launch to keep things more even power wise in a class, but plenty do reward it. Pro Solo REALLY rewards it. If doing a lot of pro solo it is basically a drag race launch each run, with 4 back to back runs, then sit in grid, 4 more back to back runs, etc. That is a lot harder on rear ends and clutches.

In a lot of cars, hard launches on an autox course, even in Lincoln, are not too bad. But with low tq cars like the S2k on sticky 255's, it is approx 6000 rpm and a pretty hard clutch release. Mine has seen plenty of those in its day !

ncrx

i recently blew up my osg diff, cracked the pressure ring and all the gears inside became little bits. it was very old with easily 1000's of launches. rebuilt it with a new osg, new RP with wpc, solid sleeve, wpc the plates, wpc and cryo'd the diff caps, arp hardware, all that jazz lets see how long it lasts.

i wonder if a 86/twin diff could be made to fit, its got a larger ring gear and all that, its a lot more stout, although not indestructible. but plentiful at least.