Woodwork

I am the woodwork and I work for American Honda.
I am writing this to hopefully help S2000 owner/drivers understand the importance of shifting properly to minimize the damage to 2nd gear synchronizer rings. I'm not the Warranty Police but will from time to time quote warranty policy when I read things like "Shifting without the clutch".

My overall objective being in the woodwork is to keep S2000 owners from hurting themselves and hurting their cars. Everytime a transmission or engine gets replaced in an S2000 I get the part. I've seen a lot of damaged transmissions.

Before flaming me please read this and keep an open mind.

You have an engine that revs to 9000 RPM. That means that the transmission mainshaft and clutch disk are also revving to 9000 RPM. When you disengage the clutch (push in the pedal) to shift from first to second the engine and the transmission are disconnected. The engine will slow down from compression when you lift off the throttle. The mainshaft of the transmission is not connected to the engine any more so it is freewheeling in the transmission. Given enough time the mainshaft will slow down but not as fast as the engine. The countershaft is connected to the rear wheels and the speed stays constant during the shift.

When you shift into 2nd gear the synchronizer of the 2nd gear must SLOW DOWN the transmission mainshaft to match the speed that the engine WILL be going when the shift is completed and the clutch is engaged.

The transmission mainshaft and the clutch disk together weigh 19.75 lbs. (not including the pressure plate and flywheel that are connected to the engine) When you shift from 1st to 2nd at 9000 RPM the engine speed drops to 5900. That means that the little brass synchronizer rings have to push on the 2nd gear to slow the mainshaft from 9000RPM to 5900 RPM. It not only has to slow down the mainshaft it has to do it in the time that it takes you to shift. So if you have a tendency to shift fast you may be making the sleeve blow past the synchro rings before it has a chance to do it's job and it will smash into the 2nd gear.

The early '00 cars needed a little change to the sleeve to make the synchros work a little harder. That is what the new parts in the service bulletin are for. Cars after VIN YT006255 already have the new parts. Grinding in a car produced later than 6255 is possible if the synchros have been damaged and now are not able to slow down the mainshaft properly.

Shifting without the clutch, or, shift too quickly and not letting the synchros do their job may permanently damage the gear, sleeve and synchros and make the 2nd gear grind more often.

It makes sense that if shifting at 6000 makes the engine speed drop to 4300 RPM, (1700) into 2nd gear then you should give the 2nd gear synchro twice the time to do the shift from 9000 RPM.

If your car does grind once in a while you may not want the transmission removed, disassembled and a new 2nd gear put in. If it does it quite often, show it to the dealer and have it replaced.

If you hesitate for another 1/2 second while putting constant pressure on the shifter while the 2nd gear synchro does it's job, I'll bet many of your cars would not grind any more. Try it. You might like it.

Added 5-2-03:
Skipping gears:
I have seen many 6th gear sleeves that have been damaged.

The typical story is this: Stop light, 1st gear, engage the clutch, rev to 9,000 RPM, shift quickly to 2nd, rev to 9,000 RPM, same into 3rd, look down and find the car going 80 MPH on a city street and the engine noise is screaming, recognize that any cop is going to write a ticket. Shift to 6th quickly to lower engine noise.

Dragging the mainshaft speed down from 9,000 RPM to 4,000 when going from 3rd to 6th takes time. 6th gear has only a single synchro ring and it doesn't like it. It will grind if you are shifting hard and fast. By shifting hard the synchro ring does not have time to slow down the main-shaft and the sleeve will slip over the synchro and grind the gear. If the sleeve is ground enough in 6th then it will not slide the other way to engage 5th.

So if it is hard to get your car into 5th or 6th it may be because the sleeve is being damaged by skipping gears. Hope this makes sense.


Woodwork
"I'm from the factory and I

VTEC Racer

Wow! Thanks! That was very informative! So if I just slow down my shift speed, will this decrease the chances of grinding? About a week ago, my 2000 model just started grinding. I'm trading it in for a new one anyways after I get the TSB done. This was good info and hopefully my new one won't have the problem if I just follow your steps. My question is though, why doesn't Honda just use stronger metals?

Cyber Logic

Excellent! That was one of the most informative threads I have read on this forum. Two questions for you.

1. So what you are saying is give it an extra split second before shifting into second? Just wanted to make sure I give this the biggest chance to work

2. I have only had my car now for 1500 miles. It has prolly happened 10-20 times...should I take my car in because of the damage I have done to my tranny or should the internals of the tranny probably have held up pretty well to have not hurt anything.

Once again thanks for the great post...and hell stop by here more often. It nice to get people that really can explain things the way you can from the view from someone in HOA.

Thanks!

johnyboy32

Interesting...thanks for the great info.

I have a question as well.

I have a MY2000 S/N 004242. TSB 054 has been done and the flywheel and pressure plate were replaced as well.

I have never actually heard the 2nd gear grind even though I have "spirited" driving habits. Perhaps I just naturally shift the way you described. Nonetheless, should I be worried about premature or excessive wearing of the transmission?

rstark

Excellent post Woodwork. Now we don't have to speculate what's going on with the second gears grinds (never happend to me). I too cringed when I saw the thread about shifting without a clucth, yes it can be done, but why would you want to.

CoralDoc

Woodwork - Thank you very much for posting this information.

John MI blk/blk '01

What causes an occasional "catch" between 1st and 2nd and from 2nd to 3rd? The "catch" could be described as subtle (not a grind) but is annoying. Is this what people refer to as notchy? Seems to happen when ambient temperatures are high and just in low rpm normal driving. Clutch pedal is fully depressed. Every shift is like this: let the rrr's drop some, push clutch fully in, pull shifter slowly and pause briefly going through neutral position and wait for the transmission to give you a sign that it's ok to put it into the next gear. I wish I didn't have to concentrate so much on the shifting. This is my 6th Honda and my 3rd Honda with a manual transmission so I'm hoping that the transmission is just "breaking in" and eventually will shift like butter like other Honda's. My Honda has 4000 miles. Thank you for the insight.

John

Frank

Woodwork, Thank you very much for the informative post. You do not need to worry about being flamed here. I think i speak for all that the main reason we come here is in search of accurate and relaible information regarding our beloved cars. I always read your posts, even when they don't apply to my particular situation and find them to be the best thing on this board. Thank you very much for being out there and keep up the good work.

Cyber Logic

[QUOTE]Originally posted by Frank
[B]Woodwork, Thank you very much for the informative post.

cdelena

OK, it makes sense. But I shift to 3,4, and 5 at the redline and don