Grinding all gears... not the clutch?
 

MY PROBLEM: I seem to be grinding gears about 1 of 20 shifts randomly. When I shift, the clutch is to the floor (I have been driving a multitude of manual cars for over 10 years), so I am certain that it's not my driving. I have tried shifting slow, fast, gentle pressure, waiting a second after pushing the clutch in, and every other shifting technique I could think of to let the synchronizers do their job. The grinding still happens with about the same frequency no matter what I do. It happens with all gears, which would usually point to the clutch. However, it seems like the clutch is disengaging just fine: I can shift into reverse no problem. When I'm cruising and push the clutch in, the revs immediately drop. I can free rev in-gear with the clutch pressed in. The car doesn't move forward at all with the clutch pressed in while in gear at a stoplight.

THINGS I'VE DONE TO TRY TO FIX THE PROBLEM: clutch pedal adjust, flush and bleed the clutch system, replaced transmission oil with Honda MTF, replaced and greased both shifter bushings.

HYPOTHESIS: Unless the clutch is just slightly engaged but not enough to prevent the revs from dropping (when I'm cruising and push the pedal down, for example), then it has to be the synchros. Isn't it sort of odd though? I don't usually hear about people having synchro problems in 1st, 2nd, 3rd, 4th, 5th, and 6th all at once! What else can I do to determine if it's the clutch? I'm debating getting a used transmission but I don't want to invest hundreds if it's not the synchros.

Thanks!

Are you up-shifting below 4300 rpm? Try shifting in the 4300-5000 rpm range.

-- Chuck

Could also
remove and grease the clutch fork in gearbox it just pulls off.
grease slave cylinder pushrod,also nipple sometimes needs removal with a file.
also red line in gears more often,it helps settle things out a little ;)

What year is the car?

Thanks for all the suggestions so far. I have tried shifting at low, medium, and high rpm with basically the same results.

I'll try to remove and grease the fork. What's the procedure for that? Disconnect slave cylinder push rod and wiggle it out? I have a lot of "clutch buzz" decelerating from 3500 to 2000 so maybe I should just replace the fork anyways... Noodels, what did you mean by the slave cylinder nipple sometimes needs removing with a file?

I was going to try GM Synchromesh Friction Modified, since I've heard it was originally designed for a GM gearbox with grindy gears. Is Redline even better for tired synchros?

The car is 2000 model year, btw. Oh and I forgot to mention that when the car is cold, it shifts pretty well. The grinding is significantly worse once heated up.

Regarding the transmission fluid, I mentioned that I was going with GM Synchromesh FM or maybe Redline. I'm open to other suggestions for sticky/"frictiony" oil.

The nipple on the end of slave rod needs to be polished when you grease it. Put rod into drill chuck, then use a suff pad while spin drill.

You mentioned clutch pedal adjusted. Did you mean the clutch rod, or the clutch pedal height? Whichever you didn't adjust, try adjusting it.

My theory is the clutch splines are dry, so clutch disk doesn't slide well. Sometimes it does, sometimes it doesn't.

Fix is drop trans, lube everything like you were doing a new clutch. But since you are dropping trans anyway, and since you have clutch buzz, you should just plan to do a new clutch. Disk, release bearing, release bearing guide if needed, possibly pilot bearing. Resurface flywheel and pressure plate.

Thanks for the clarification. I'm doing the work in my driveway so I'd like to avoid dropping the transmission if at all possible. I'll need to think about how/when I could do that. I wonder if there's any remote possibility of getting some sort of spray lubricant into the splines without removing the transmission completely. Then, if I notice improvement, I could do a full clutch job. Also, I only adjusted the clutch rod. The height seemed fine, but I can adjust it anyways just to eliminate that possibility.

I fought problems with my year 2000 transmission for years that was very frustrating especially when the box was hot . This is from when the car was new and Honda was no help. There was a TSB regarding poor shifting back in 2000 (claiming a stacking tolerance problem) but me and few owners that I talked to were not happy with the results and I knew a couple that sold off their cars and swore off Honda products.

It finally crapped out and I bought a transmission that was in a 2002. What a difference! It shifts smoothly every time regardless of temperature and is a pleasure to use. My only regret was waiting so long to replace the transmission. It was a relatively cheap fix and transformed the car.

I think there was a run of bad boxes early in the life of this car and replacement with a later transmission is the only real fix.

this is interesting.

maybe related to the synchros?

did you tear down the original transmission to see what was going on?

You can try to get grease in there but it's very difficult to see what you are doing and you don't want to get grease at the wrong place.
I had similar problems and used a bent piece of wire to get the grease in at the right place.
You can check this thread for more information https://www.s2ki.com/forums/s2000-un...lutch-1157540/

No, I have no experience working with that and did not really want to. Honda had already replaced shafts and gear sets (tsb and warranty) with no dramatic improvement. When it gave up and just researched what was available from the local salvage firm and was able to pickup a low mileage 2002 transmission for about $550. Put it in myself without problem. I have been told that parts alone to do a full rebuild is more than that.

Ok so for a quick update, I did grease the everything I could find at the fork/slave cylinder, polished the slave cylinder pivot ball, adjusted the pedal height, bled the system (again), and tried red lining the gears a whole bunch. Pretty much the same.

I did get some new info though (I've only had the car for a month, btw). Shifting from 2nd to 3rd the other day, at about 4500 rpm, I pressed the clutch to the floor, and the revs stayed at 4500 rpm. I got the engine/transmission to disengage by blipping the throttle a bit, but clearly the clutch is sticky. I guess the title of the thread is wrong because it must be the clutch not disengaging. Also, I went to a flat parking lot and experimented shifting from N to 1st with the clutch on the floor. The car nudged forward a bit even while the clutch was depressed.

Ugh I do not want to replace the clutch in my driveway but I'm way too cheap to have a shop do it, so I have a really dumb idea that I want to try first that I want to run by you guys. There are several reasons that the clutch might be sticking, but one of them is a friction disk that fits too tightly between the pressure plate and the flywheel. The car is sort of beat up (salvage title, paint is rough, some maintenance items were a little overdue), so I'm thinking maybe the previous owner installed a cheap or mismatched clutch kit. Should I try to wear down the friction material a bit to get more clearance and possibly less sticking? It would be free (all I'd have to do deliberately drive terribly by slipping the clutch), and what's the worst that can happen? It's either change the clutch now or wear it out and change the clutch...

I don't think this is possible. Too thick of a clutch disc would make it hard to reassemble the pressure plate onto the flywheel.

Sorry. :(

Yeah... wishful thinking.

So is the clutch replacement doable in a driveway? The diy links I've seen show the car lifted.

Many clutch swaps are done on garage floors so I don't see any reason it cannot be done on a good driveway. Since the car must be raised quite a lot and put on heavy duty jack stands to drop the subframe and remove the transmission it is not something you would want to do or leave unattended in some neighborhoods.

Probably nobody cares but I thought I'd give an update in case anyone else ever has this problem. I drove the car for a few months by carefully rev matching it since the clutch was semi-permanently engaged during a lot of shifts. It was getting worse so I made time to finally drop the transmission and replace the clutch. The problem was that one of the clutch disc spring retainers (the piece of bent metal holding the springs in place) broke off and was floating between the disc and pressure plate. It was rubbing between the two, gouging into them, and keeping the disc coupled to the PP/flywheel. I guess the piece wasn't always wedged between the PP and disc since sometimes the car would shift okay. I think I'll upload a picture of what happened later on.

By the way, replacing an s2000 clutch on the floor is a nightmare. I had 3 subframe bolts and one transmission bolt seize up badly during removal (the trans required rethreading). The front right subframe bolt was so seized up that I could not lower the subframe very much which made removing the transmission difficult. One of the subframe captive nuts broke off inside the frame so I'm permanently one subframe bolt short (anybody got any ideas to fix this?). Then, every single bolt on the driveshaft stripped because someone before me tightened the absolute piss out of them. I had to cut the heads off (I replaced them with regular grade 8 hex head bolts which are a ton easier to work with, by the way). I'm guessing it took 200 ft.lbs. or more to remove the flywheel bolts (double the proper torque)... If everything goes right then maybe it wouldn't be so bad, but when you encounter problems it can be difficult to fix them with such little clearance under the car. Power tools like an impact wrench would have probably also helped...

The car is so enjoyable to drive now.

Thanks, for the follow-up. Always helps to know the culprit & final outcome. Was the defective clutch an OEM Honda one or an aftermarket type?

Thanks!

:iagree: :wine:

Nice to know it's fixed!

-- Chuck

Actually follow ups are very important, and appreciated.

Seen the broken/floating piece of spring cage quite a few times.

Yup, mine failed the same way. Previous owner installed the crappy exedy so called oem (its not oem), which is famous for this spring failure.

No need to show us a photo, we've all seen it before.

Glad you got it fixed!

Even 2 years later I’m very happy with your update!

I’ve kinda got the same symptoms. The box shifts very smooth if I revmatch, if I don’t then sometimes it feels like I have no synchro’s at all.

I think that the problems get worse when the gearbox warms up. At first it gets more difficult to shift into the higher gears, then the lower gears start acting up too. If I want to downshift into second gear I need to get the revs up really high, and when they match it shifts quite smoothly. If I’m not doing that it feels like hitting a wall.

the car has been sitting for a year, so maybe I should grease some things. I think it still has the original clutch in it, the car has 150k km on it.

Basically the car shifts very smooth when revs are matched. If not it feels like I have no synchros at all. Clutch seems to work perfectly, I can rev and shift easily when standing still, the car doesn’t move

Not a very valid test. The amount of clutch drag required to move a nearly 3k lb object that is at rest (objects at rest tend to stay at rest) is way more than would be required to keep several pounds of rotating mass inside trans to remain rotating at engine speed (objects in motion tend to stay in motion).

So you could easily have enough drag to cause grinding but no where near enough to make car move.

Your symptoms are consistent with clutch drag, and I suspect that is indeed your issue.

If fluid isn't clean and clear, do a full bleed using gravity bleed method, making certain reservoir never runs dry during process.

Next adjust clutch rod.

If there is still symptoms, try adjusting height of clutch pedal to raise height for more total pedal throw. If this step makes a significant improvement, you have an internal issue with clutch. Something like rusted splines, guide is not smooth, insufficient or wrong lube, or a crappy Exedy so called oem/ebay disk that is starting to drop a spring. Only fix is to drop trans and address, and at that point it just makes sense to do a full clutch job. Drive with higher pedal height to ease further damage to trans while you plan for clutch job.

Thank you very much for your insights! I did a full bleed, but since the fluid was very dirty, I might have made it worse. There is also black junk at the outside of the master clutch cilinder, so that one has to be renewed. I've adjusted the clutch rod at the master cilinder too. I haven't found how to raise the height of the clutch pedal though.

There is new MTF3 in the gearbox too, so when it shifts smoothly, it's really smooth.
I've stupidly been driving the car the last few days for a few 100kms, and know I notice extra noise at constant speeds :(. The car also sometimes wants to move with the clutch in, so maybe it's just the master clutch cilinder on the way out..

I doubt its the mc. They rarely really go bad to the point of allowing drag (if tbey are leaking, usually just flushing woth new fluid resolves it. Though sometimes if fluid is dirty enough, for long enough, they can develop leaks onto carpet that persist even after fluid is flushed.)

I wouldn't be surprised if its a crappy aftermarket clutch disk that is starting to drop a spring. Often the spring moves around and sometimes drags and sometimes doesn't. Or sometimes drags more or less. It slowly gets worse until one day spring drops completely and clutch locks up solid.

Just as an FYI on this, they can leak in a not so apparent way up front. My master cylinder failed during an autocross a few years ago. Kept losing fluid, but never saw any fluid anywhere. It acted as if it was leaking once it got hot, then stopping. I topped it off, drove it home and started feeing all around under the dash. No sign of fluid. Did notice a small amount on the firewall under the cylinder. Jacked up the front to put the car up on stands, and it came pouring out onto the garage floor. It was running down and under the firewall on the engine bay side and was collecting on top of the plastic undertray right there under the driver side floorboard, so it was not dripping, or not enough that I ever saw it. The only sign of where it was going was when I got under the hood with a light and saw the small stream that had run down the firewall In the boxes of spare parts the previous owner included with the car was a brand new Honda MC still in the package. I assume it had leaked once before, then stopped, and so he never replaced it. So that was an easy fix since I already had the part there.

...and while this is a rare failure, it shows they do sometimes fail. But even if you have such a failure, you'd know something wasn't right as you'd be losing fluid with no obvious wet area.

^^ yep mine is the first I have personally heard of actually failing. It was odd af first. I noticed it was not right, found the fluid was low, topped it off so I could finish the event and it was perfectly fine for a bit when I checked, then lost a good amount again in the afternoon. That is why I suspect it was mainly occurring after multipe runs (it was a practice event, so probably 30-50 runs in a day) when it would get hot. So likely a seal going but not totally gone yet. And I was pleasantly surprised that I did not find hydraulic fluid soaked carpet when I got home :)

I kinda have the same problem with my clutch i have an AP1 '01 at first i was annoyed by the so called "clutch buzzed" i went in and bought a OEM/ACT clutch combo w/ streetlite flywheel. After breaking in the clutch around 1.5k miles with them, i noticed that every time i shift starting from 2nd gear to the 6th gear i always hear that grinding noise, to tell you ive been driving manual for over 6yrs now and i know for a fact too its not my driving. Every time i drive my Civic Si the same way i drive my s2k i dont hear any grinding or what ever noise coming in from the transmission or clutch. At first i thought i would go away but recently this shit just gets annoying and whats weird is that when tried to up shift from 2nd to 3rd and 3rd to 4th so on an so fort, just like how your start from first gear that you have to slowly release the clutch and give gas it wont make that noise. I already have the master cylinder replace, transmission fluid done and new clutch kit. Im hoping regreasing the clutch fork, replacing the slave cylinder and adjusting the engagement point of the clutch will help.

Who did the clutch replacement? Did they properly grease everything per the manual? Did they use Honda Urea grease? Was the clutch bearing guide also replaced when clutch was done?

If the answer to any of these questions is no, or even if its I'm not 101% sure, then that is likely your problem.

Clutch isn't disengaging smoothly, and its dragging slightly. Just enough to interfere with syncros operation.

ACT HD Pressure Plate, ACT Street Lite 11lb flywheel. ACT Clutch Alignment tool. Honda OEM Clutch Disc. Honda OEM Pilot and Release bearings. this is what was change on my clutch so i dont think the clutch bearing guide was replaced. I bought my car to a shop here around in SoCal they are pretty reputable shop for s2000 and it was change like 2 months ago or id sad 3k miles ago.