So if I take the gear box out to rebuild the synchros, what else should I do?

Look at the tolerances very closely?

Look for alignment and meshing of the gears,

Whats the thoughts on this?

 

I almost missed this part of your post before, and it may be one of the smartest things anyone has said so far.

I think you are absolutely right, though I might say it a little different. I'd say that we make different allowances because we have different expectations. I certainly have certain expetations for roadsters and sports cars, and the S2000 meets most of them in spades. When I first drove the MY00 AP1 I felt as if I was driving a car that had been built to my own specifications, becaue it matched my driving style and expectations so perfectly. It almost seemed that Honda had somehow read my mind. I've had the car going on four years now, and haven't found anything to change that perception. There are things I absolutely love about the car that others find objectionable, but it's always that way with a specialty car. LOL, that's what makes them a specialty car in the first place.

 

Very good questions, but since I don't have any problems with my transmisison I'm probably the wrong person to try to answer them. Since my stock box has performed flawlessly for seven years, taking the worst I could throw at it without complaining, I wouldn't consider replacing it with anything other than an identical stock box. If I could find a good used transmission I might go that way, or I might just fork over for a new box from Honda. If it ain't broke, don't fix it (and for me the S2000 transmissions are anything but broken, so I'd stick with what works).

If I were to decide to have the original box overhauled I wouldn't settle for anything less than full blueprinting. (Which is basically looking at the tolerances very closely.) However, if you're unhappy with the shift action of the stock box I don't really know how you'd change things to be more to your liking. I wouldn't want to change it at all, unless I was putting a crash box in the car.

Sorry I don't have a better answer, but the questinos are good.

Anybody else?

 

Hm. I graduated from a '95 Integra LS to an '01 Integra GSR and then to my '06 S2000.

I don't generally have trouble with shifting in the S, even a redline 1>2 shift. No grinding at all. I wouldn't even be aware of this being a problem except for the forums.

Don't know why. Maybe I'm just lucky. I don't consider myself particularly skilled. I'm just enthusiastic.

Maybe I don't grind because I'm not quite enthusiastic/skilled enough?

 

That would be a nice start as to my guess, but I would note what gear is grinding or causing problems and just follow the total TSB for it, this has been hondas proposal and so far i have heard good results following the corresponding grinding TSB.

 

um im planning on a dog box or TH400 swap

 

That sucks, worse than getting three bad Miata alternators in a row, but unfortunately, sometimes that's the way the cookie crumbles. I gotta give you props for sticking with the car. I'd probably have thrown up my hands after the second bad transmission and dumped the car.

Were all your problems related to grinding/crunching? When you were having the grind/crunch problems could you drive around it by shifting the way you would with a crash box? Did anyone take the bad boxes apart to see if they could determine the cause of the problem?

LOL, sorry to be asking so many questions, but I'd like to get a better idea of what's behind the problems you had. We haven't seen this kind of thing yet, but sooner or later somebody is going to come into the shop with the kinds of problems you've had, and the more I know about the failure modes when that happens the better off we'll be.

 

I would expect a design flaw to be more consistent. According to posts in this thread, some tranny's work great, while some have issues. I have only driven my own S and one other for a short test drive.

Maybe the problematic ones have worn parts (synchros or bearings) that exceed the tolerance limits necessary for proper function?

 

Their are many complaints at my dealership on this issue.The bottom line is its a design flaw!I like hecash have dealt with this problem since owning this car.I even rebuilt the transmission myself and it shifted perfectly for around 3k and then the 2nd gear grind on upshift started again.I replaced the entire box with a brand new my 04 unit and while the problem has somewhat improved it still exists.You just have to adjust youre shifting methods to accomodate this car.I still love this car as its the most fon car ive ever owned!

 

I can't speak for anyone else, but I greatly appreciate your taking the time to answer my questions. Like I said before, we haven't seen anything like this *yet*, but I'm sure we will sooner or later. Are you up to answering a few more questions and/or responding to some speculation?
I don't want to be a pest, but I want to understand this issue as fully as possible.

I suspect that your second failure, the one after the Honda dealer replaced the synchros, was due to the fact that they fixed the symptoms rather than the cause. Odds are that something out of spec in the box caused the first and second synchro failures, and all the dealership did was replace the synchros, without looking for the cause. They simply assumed that you yourself had trashed them, and that probably wasn't the case. Since the transmissions have a good record for reliability (looking at the broader statistics) this seems more likely than a design flaw.

The first replacement transmission was used and may have had mushroomed synchros (or other issues) due to abuse from the first owner. When you look at the number of people who have trouble shifting their cars when the box is cold (and at other times) a used box is a bit of a crap shoot. I dare say that nobody would ever buy a used MGA transmission without expecting some second gear synchro damage, and while the S2000 box has a much better reliability record, we face a similar situation. Used gearboxes will always be a bit of a crap shoot.

The second replacement transmission was new, but it had been in a train wreck. I really don't have enough time in AP2's to say anything about their gearboxes, but who is to say that the second transmission wasn't either defective from the factory or maybe even damaged in the train crash?

The fact that the first transmission had a problem and falied again after being repaired by a Honda dealership isn't really that surpriseing. Spit happens. The fact that the AP2 transmission had problems after being in a train wreck isn't too surprising either. Murphy is a PITA. However, having it all happen to the same guy is odd to say the least. LOL, you're not carrying around a lot of bad karma, are you? j/k

If I'd had your experiences I would also be thinking that the design of the transmission was probably flawed. I think we're about the same age and have similar experience, so you can easily put yourself in my shoes. I've driven a number of S2000's and they all shift like a dream. I've helped a number of people who were grinding figure out why it was happening, and (so far at least) it has always been a driver issue rather than a problem with the gearbox or clutch. I treat the S2000 gearbox the same way I've treated every other gearbox in every other car I've ever owned, and it's taken everything I can dish out and still shifts like a dream. I also look at reports from JD Power and the cars we see at the shop and everything I see and have experienced seems to say that the design is not flawed in any way. A good driver (which you are) is not likely to have any problems at all, and most drivers adjust to the cars quirks pretty quickly. Others need a little help, but most people have one to three problems with their car and the gearbox doesn't seem to be on the list any more often than anything else. I'm not trying to say with absolute certainty that there isn't some major flaw in the gearbox design, but I hope you can see why I don't see it the same way you do.

LOL, you could bet your last dollar that if I'd had the same experineces you've had I'd feel differently, and we wouldn't be having this conversation.

I got three bad alternators for my MX5 in a row. The alternators are not known to be unreliable, so I'm sure we can agree that my experience was a fluke. Every one of the alternators had exactly the same problem, shortly after being installed on the car, and I suspect that there was simply a batch of defective parts that slipped into a production run. That's not really that uncommon. It also could have been that one of the machines used on the production line was out of spec during all or part of a production run, resulting in a number of out of spec products slipping through. The fourth alternator has continued to work flawlessly for months (the others failed in a matter of days or weeks), and that, plus the reliability record of first gen Miata's, I can't believe that my problems were the result of a design flaw. I do believe that all the failures were the same, and I also believe that it was the weakest part of the design that was failing, so the failures could have been prevented if the design compromises had been somewhat different, but I don't see any way that such things constitute a design flaw. I just had a run of bad luck. LOL, Mazda was having a run of bad luck too. Murphy is a jerk.

Can we agree that we can't know with certainty that your series of problems wasn't similar to my situation with the alternators? If we can't, then I might be totally wrong, so please don't hesitate to tell me if you think I'm full of crap.

Thanks for taking the time to go through this in so much detail.