Chuck S

If you missed post #13 go back and read it. 'Nuff said.

-- Chuck

davidc1

Woodwork was a guy that worked at American Honda (HQ) in Torrance, CA. From what I remember he was an engineer who inspected parts replaced under warranty by dealers to determine why a part failed.

I sure wish I had read his posts before I ruined my tranny by skip shifting. I had skip shifted many cars before my S2k, so I just assumed it wasn't going to hurt it either. Here are a few quotes from Woodworks posts about it. (I wonder where he is now...?)

Hi Guys:

I have some transmission parts on my desk from my customers who skip gears. If I knew how to post photos I'd send them.

The problem with skipping gears is the same as shifting from first to second very fast and making it grind.

There are Double cone synchros in 1,3,4 single cone synchros in 5,6,R and a triple cone in 2nd.

As I have posted before, if you shift quickly from first to second and you don't give the 2nd gear synchro time to slow down the 19 pound main shaft to match the next engine speed, then you will grind the sleeve as it contacts 2nd gear. All you need is constant pressure and 1/2 second on 2nd gear. If you put too much force you don't give the synchro time to slow down the main shaft before the sleeve hits the gear.

The same is true for skipping gears. Honda does not recommend it but if you are going to do it any way you just have to give a little more time for the synchro to do it's job. Double clutching on an upshift is good, if it is done correctly it will slow down the main shaft. It probably takes as long to double clutch as it does to just wait for a half second and let the synchro do it's job.

I have photos of all this. If I put it in a Word document could someone post it somewhere?

HTH,

Woodwork

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Hi All:

Just back from out of town.

I have seen several 5-6 sleeves that have had extensive damage from doing the 1,2,3,6 shift.

The 6th side gets mushroomed from pushing past the 6th gear synchro and grinding on the 6th gear. Then because of themushrooming the sleeve won't slide backwards into the 5th gear.

I was going to send someone photos of this I think? xviper?

Any way, usually the complaint is that it won't go into 5th gear but in this case it sounds like it is not going fully into 5th.

My suggestion: Have the dealer remove the transmission and replace the 5-6 sleeve/hub and 5th and 6th gears. (synchros come with the gears).

HTH

woodwork

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The more likely situation I have seen many many times is where the 6th gear gets used like this:
Start out hard in 1st, get to redline,
shift into 2nd, take to redline,
shift to 3rd, get to redline,
shift to 6th to get the engine speed (noise) down quickly.

The problem is 6th gear sleeve gets ground into 6th gear because the synchro on that high of gear isn't meant to take the mainshaft speed from 9k to 4k.

Now the sleeve is damaged on the 6th gear side and won't slide backwards over the hub into 5th gear.

Don't do that.

Woodwork

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davidc1

Ahah!!

Here's the post from Woodwork I was really looking for, along with a service bulletin that Honda sends out the the repair departments of it's dealers....as Chuck S already said...."enough said".


This is from the January 2006 Honda ServiceNews:
"Skip Shifting Is Brutal on Synchronizers"

Gear ratios in 6-speed manual trannies are spaced
close together so you can keep the engine speed
in its optimum range for max power and
acceleration. Shifting to the next higher or lower
gear in a close-ratio tranny causes small changes
in engine speed.
Shifting a close-ratio tranny through its gears by
the numbers puts a very small load on the
synchronizers since they only have to make small
changes to the speed of the mainshaft and the
clutch disc.
Some drivers, though, like to skip shift so they
don’t have to work the clutch pedal and shift lever
as much. They like to accelerate in 1st gear, then
pop it into 3rd gear, then into 5th or 6th. Skip
shifting, though, is really brutal on synchronizers;
it puts a higher demand on them than they were
designed to take. Skip shifting can cause
premature synchronizer wear that can cause the
gears to grind when you shift up or down.
If you’ve got a vehicle in your shop for repeated
damage to the synchronizers, go for a test-drive
with your service customer to see if he or she is
guilty of skip shifting. If that’s the case, remind
him or her skip shifting can be an expensive habit
to break. Any repairs due to skip shifting may be
reviewed and debited by your DPSM."

Here's another post I found explaining the S2000 problems he has seen:
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.

jyeung528

that is an answer to an OP question if i've ever seen one.