OP, I believe it may be the shifter, and I'll tell you why. Years before I bought an S2000, I sat in one at a dealership. The shifter was literally like cutting through melted butter, thats how smooth it felt. Feel your shifter with the car off now, Is it smooth? Mine is far from it. It's a small workout just moving it around. I believe it's the shifter needing grease, the spline would technically be completely unrelated, right?

 

That's my point. Yours are not, but do you know for a fact that they were that way from the beginning? You really don't have evidence to say if yours was rusted to begin with. You say your dealer did a clutch job just before you "cleaned" and re-greased them. When your dealer first saw the splines, they were probably rusted. When you next saw it, you cleaned it. What was to clean if it wasn't rusted?

 

Possibly but not necessarily. If the splines are so badly rusted that the disc cannot slide easily, then it cannot properly and fully disengage. If there is even a small amount of power being transferred into the tranny, the shifting will feel rough and notchy. Like I said, even with rust present on those splines, the disc will still be able to come free of the friction surfaces.

 

Even with the car off?

 

Yes, it's possible. It depends on at what point the engine stops turning relative to the position of the clutch. This determines whether or not any residual resistance is being placed on the input shaft of the tranny. Try it sometime. Turn your engine off, then release the clutch. Now try to pull the tranny out of gear and then try to put it back into first. Sometimes, it'll go easily while other times, it just won't go. On those times it won't go, push in the clutch and try again. Then it goes. If the the disc is not able to move away from one of the other friction surfaces due to excessive rust or nicks in the splines, it still won't go in easily. You'd have to try for one of the higher gears just to cause some of the tranny gears to nudge enough to make first easier to engage. But if you've got any kind of experience with operating and working on manual trannied cars, I shouldn't need to tell you any of this.

 

Rusted and/or improperly greased input shaft splines can cause notchy shifting is the point of my post. Since I (and others here) have properly cleaned and greased our splines the problem has not returned. HTH

 

@ xv:
It was a bit of a word game: you say all splines ARE rusted, as in present tense (right?)
So I answer: I know (*) mine ARE not (as in right now)
And yes, they (still) were rusty before I installed the clutch myself AFTER the dealer did, IOW they did not clean etc.
They didn't even use grease.
As a result the shifting still was not as good as it IS today and has been since I took care of the splines, on both the input shaft and the disk, btw.
I assume the splines were not rusted when the trans was mated with the engine in 1999 and I assume they used grease back then as well.
But it didn't last for 5 years as I found rusty splines.
(*) So maybe I should have said "I assume" my splines are not rusted as I haven't seen them since the last clutch install.
Going by the way it still shifts and knowing what type of grease I used I'm pretty pretty pretty pretty pretty pretty sure they are good.






Anyway....

 

OK, ol' buddy. I now see your word game and understand your post. As you may recall, I purchased a brand new AP2 tranny direct from my local Honda dealer. There wasn't a hint of rust on those splines when I opened up the box and Honda did not package it with any grease on the splines. I greased it well before the install but I would almost put money on it that if I had not done this, rust would have formed within 6 months and even with the grease, I think rust would form after a couple of years.
BTW, my old tranny came out with the splines rusted like crazy and I can tell you that the shifting of the old AP1 tranny was just as smooth as the new one.

 

For some reason, the phrase "rusty splines" makes me think about other things than rusty splines.
But I can't really visualize what I'm thinking about.
It must be me.


Anyway.. I did notice an improvement in shifting with lubed splines.

(the same is now happening with "lubed splines", I think I'm gonna bail out of this post real quick)

 

OP, I regreased my shifter. What a difference. DO IT.