S2000 Under The Hood S2000 Technical and Mechanical discussions.

3-2 downshift grind

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Old 05-24-2012, 04:08 AM
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Default 3-2 downshift grind

I have had my s2k for about 2500 miles now and on occasion it will grind shifting from 3-2. I never know when it's going to happen, clutch fully depressed etc...has happened in normal driving conditions and some spirited driving,maybe 8 to 10 times now. Any ideas? Took it to Honda and they can't replicate (of course).

Thanks!
Old 05-24-2012, 05:57 AM
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Not sure if this might be your case
I had one of those moments once or twice too, but then it's because I didn't shift into 2nd fully (I usually shift really soft and the lever sorta pulls itself into the gear smoothly, so if it pops back out I would know), happens a lot when the car is cold

See if this is the case. If you shift fast into the gear and then release your hand, there's a chance that it probably popped back out half way without you knowing, and hence the grinding sound.

Just a possible situation though! Hope you have it figured out soon!
Old 05-24-2012, 08:35 AM
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I see you have an AP1 so maybe this is a basic syncro gear issue on a 10yr old car. They could be worn (starting to grind) or in need of replacement. However, first thing is swap out your manual transmission fluid, making sure to flush it out thoroughly. Could possibly be a need for a flywheel adjustment? If after you swap the fluids, you still get the occasional grinding, try rev matching your shifts to lessen the burden on the syncros. If that makes the difference, you can zero in on them more so. Isn't is sad that downshifting feels and sounds so good but is basically death of the clutch system? =/

I read on here somewhere that AP2's have a (C)lutch(D)elay(V)alve which manipulates the speed at which shifting into each gear will happen (slower). If maybe shifting down too fast and forcing into gear, maybe the gears might have a grinding noise to it. CDV swaps from AP1s to AP2s seem to be common enough that maybe a previous owner did the opposite on yours?
Old 05-24-2012, 08:53 AM
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adjust the free play in your clutch pedal accordingly to billman's recommendation.
Old 05-24-2012, 09:56 AM
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Syncros only work so fast, so its important to rev match as that will decrease the time they spend working. Since the lower gears (2,3) have bigger ratio differences, its more important to get close when changing. don't shift too quickly either.

Do you know what rev matching is?
Old 05-24-2012, 09:58 AM
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Originally Posted by jguthrie
I read on here somewhere that AP2's have a (C)lutch(D)elay(V)alve which manipulates the speed at which shifting into each gear will happen (slower). If maybe shifting down too fast and forcing into gear, maybe the gears might have a grinding noise to it. CDV swaps from AP1s to AP2s seem to be common enough that maybe a previous owner did the opposite on yours?
This is all incorrect information. The CDV regulates clutch engagement so it doesn't happen too fast and shock the driveline, which led to broken diffs in the early cars. It doesn't slow the engagement, just keeps it from happening too fast.
Old 05-24-2012, 12:45 PM
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Change your clutch fluid.

That is all

Also, do you rev match?
Old 05-25-2012, 02:44 AM
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Thanks for the replies.

I will try the clutch fluid, though when I bought the car I was shown the work order from the Honda dealer and it has a new clutch so I assume new clutch fluid was put in.

"Do you know what rev matching is?" Really? I ALWAYS rev match so that's not the issue, oh and I can heel toe too...
Old 05-25-2012, 04:22 AM
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I can almost guarantee they didnt touch the clutch fluid. When you flush it out and get some good stuff in you will notice a big difference. Post back when it's changed, Im curious to hear your results.
Old 05-28-2012, 03:11 PM
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Originally Posted by FluKy15
I can almost guarantee they didnt touch the clutch fluid. When you flush it out and get some good stuff in you will notice a big difference. Post back when it's changed, Im curious to hear your results.
Just changed it, much smoother and silky, feels really good. Just drove a couple miles so we will see if the 3-2 grind happens now. Fluid that was in there was gray and dirty.

Thanks!!!!


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