Originally Posted by wrencher

My mission is to find out if an external filter could have saved this tranny.
About me- certified professional wrencher- but not for this brand
Been around long enough to have seen honda push their CVCC technology as a selling point. So yes I know how to use my wrench!

Even though I see by the posts that most here are DIYers ...i think a few will appreciate some diagnostic/repair info. I'm out to find the cause...not just overhaul. Keep in mind that most of this repair is beyond the scope of "weekend mechanics". but your welcome to try....just baggy and mark down location of the hundreds of pieces in the transmission as you open it

Picked up one of these 7th generation automatic civics with a tranny problem. Intermittent engagement of R D 3 2 and then slip and loss of all engagement after 2 minutes of driving
Didn't know better at the time and figured it was electrical! NO!


So this civic suddenly lost all forward and reverse gears. It has 200k + km on it. fluid never smelled burn't. maybe it slipped a bit prior to total failure - maybe not...guess we will never know.
Fix diagnosis:
Fluid was fully flushed with tranny flusher and it then intermitently would engage D or R .
I read up on this issue and found it was common and internal....but mine was intermitent and when it ran- it worked great shifting points good ect.. Seeked wisdom from peers at other brand--->Guess what??? dealer doesn't even open these transmissions up for service. HAHAHA! Tech suggested to check selenoids so I removed, cleaned, bench tested selenoids. Wasn't the problem. I started to notice a pattern develop: car sits > it engages. car runs > it eventually whines (like power steering pump) and starts to slip then drops the gear. let it sit off long enough and it re-engages. Tightly packed fiber residue on strainer could partially restrict suction. Could it be a blocked strainer (pickup tube filter) could it loosen when sitting? Another post on this forum , of a similar problem and eventual fix, sparked my curiosity. But he changed so much (opted for a full rebuild) I got the facilities, knowledge, and resources, some time....lets play!

The inspection: So I am assuming that it is a blocked strainer. But no pan on this model- and it isn't easily serviceable. I dropped the fluid ( 2+liters)and shoved an inspection camera through the drain hole. guess what: the strainer looks inline in the diagrams ....but i can"t see it with my cam...lots of bolt heads and gears in the way....but no strainer!

plan 2: lets try to partially clean/flush it out in place with brake cleaner (use it all the time to clean valvebodies on overhauls). I blow compressed air and brake cleaner through drain and fill hole. All over the inside, bound to hit that strainer I hope. Messy!...some fiber residue coming out.

fill and run: it engaged! Ran in gear for couple of hours on lift. drop and roadtest... was great for first 10 minutes then poof! Starting to slip... but still engages gear. Took line pressure: low at 110psi and little volume (or internal leak). But the pump is whining so probably not internal leak. Really sounds like a blocked strainer now .

decision: Drop and rip open for inspection:
Was a very easy drop. Opened the case.- Yup, strainer is plugged up with fiber residue. Inspect clutch packs- all in good condition except 2nd fibers as expected are quite worn and metals slightly discolored. 2nd clutch installed clearances slightly excessive so why not change...But not so bad! could probably close it back up with old 2nd packs (but for 24$ oem) Yes Got pics! All seals are good on mainshaft. Was it really the strainer. Cleaned it out ---like new now.( Yes they are cleanable like any other screen!). check valvebody- all good. gonna gamble on not checking pump. my brand requires special alignment tools for pumps...and i have never seen a pump failure to date....only valve jam/spring brakage.

What should i do about the torque????- 50/50 decision here. some of that residue may be caused from the lockup clutch inside the torque. But then again ...never had a lockup code. I'm chancing it! Gotta keep all variables to a minimum .Gonna clean it and try with old torque. Worse case scenario...i need to sacrifice another few hours to put in a new torque if it codes....(and few hundred$$$)
Parts on order. sticking to oem so i don't need to wait for delivery...and recalculate all my clearances/shims. Should be back together by weakend ...maybe if i have time. For sure going with an external trans inline filter also. honda wants $30+ for the one from the Fit....going jobber for now.

Any questions or requests please ask now while it"s open



Not too dirty inside



2nd fibers and steels- slight wear (measured) and glaze from slip



4th fibers for comparison (same part)



After cleaning 2nd steels



No.thats not a new strainer...just a cleaned out one.

Originally Posted by wrencher

Here you go:
unfortunatly not much to see, as all the "good stuff" is inside and welded shut. FYI: Torque converters can be sent out for testing.



transmission side




Know its blurry...If any out there is going to replace a transmission. keep a close eye on that Oring just below the ATF pump engagement splines; it is very important....




flexplate side (motor side)

Originally Posted by wrencher

Since many like pics:

The Assembly:


Good view of assembled mainshaft and secondary shaft.

For those wondering: from left side . mainshaft with 4th gear(top below gear) and 2nd gear (bottom) clutch drums. They are stuck back to back on this model. The clutch fibers, steels and pistons are all within those drums.
Shaft on the right is secondary. The single clutch drum (at the bottom) is the 3rd clutch... that bigger flat gear right of that is the differential gear... your right driveshaft pops into that hole in the center of it. that big hole in the case is for the starter motor... that selenoid at the left is the famous torque lockup selenoid!

pay attention to those little holes in the clutch drums...i will be refering to them later in my writeup/conclusions.




Other side . With valvebodies...and a good look at the installed strainer/pickup tube




top view




all around

Originally Posted by wrencher

Now we put the center part of the case on and we start assembling the last bit. The Park pawl (lock) and 1st gear clutch.


That toothed wheel and matching locking lever is what locks your car from moving when in Park. In this case its not rounded at all.....so the driver never slamed it into park while vehicle was still moving!

the clutch drum is 1st clutch. on the left










And it's all closed ... and in the car....now the write up. conclusions....opinions

remember ... I inspected/measured all inside...but only cleaned the screen (strainer/pickup tube) and replace 3 not so worn 2nd clutch fibers (24$ OEM). (Also the 2 case gaskets cause you can't save them)...

My mission was to know what was happening to this transmission (and maybe many others). Could anything have saved it?
The results tomorrow...and line pressures etc....need a couple of cold ones now....

Originally Posted by wrencher

Flushed external cooler, topped up transmission, spun it up on lift and filled all internals, leveled the fluid....


My findings and opinion. (remember these are my personal opinions)

Yes it ran great.shifted solid, yet smooth. Before even roadtesting I hooked up my guage to see if line pressure/volume had increased . Back to spec at ~134psi@2000rpm. But biggest difference was volume- when gear selected, the clutches would fill up quickly. Pressure increase was instant accelerated in any gear.
So there you have it! the internal screen was the culprit. So what caused all this fiber? In all honesty there wasn't that much fiber debris. a little from all the other clutchpacks and a little more from the 2nd. I've rebuilt many "other brand" transmission where 4, 5, 6 fibers where down to the metal, the trans oil looked like diesel oil (black). The smell made me wish i was wearing a respirator.....and yet line pressure was good- no pump starvation.

Are those 2nd fibers defective? NO! I think too many people are using the wrong word. Could they have improved? YES (and i hear they now have a new material?)- maybe to a longer lasting, finer debris material! Simple proof that they are not defective is that 4th clutch uses the same fibers- and they are usually OK.
The big problem to me is that screen is too fine/too small for it's "liftime" use. It should be able to hold at least all the fiber from all the clutches reaching their service limit and still provide adequate passage. It's a catch 22. The partial blockage causes a drop in volume/pressure, some slip occures and the fibers wear out faster causing more blocking material. The harder one drives this transmission the faster this wear happens. All in all not a transmission made for abuse (only 3 little fibers per clutch).
2nd gear also takes the hardest "hit". Driver floors the accelerator from stop. First engages (already engaged) and we are off. Converter spins over torque stall speed- our converter now has minimal slip. bang it hits second gear. the engine is just under redline. The converter has no slip mercy and the engine has spun up so much momentum, the wheels won't give any slip either! That little clutch is trying it's hardest to lock up! That hard work ate at some of it's friction material . it locked. Engine rpm drops! car almost redlines again... already wizzing Past any legal speed limit (unless your on highway). So you back off,,,quick upshifts 2-3-3-4-cruise. Or not...
Hard acceleration city downshifts will also usually hit 2nd hard.

They could have made it stronger/ more discs/revised part- but can the PCM "learn" shift times and adjust pressures accordingly? can a new shift curve be flashed into PCM? (whole other subject-sorry)

So would that external filter have helped? Yes to a certain degree. If finer than the internal it would "catch" some fiber therefore helping the internal keep cleaner. A slightly coarser internal filter screen would be in order. The larger chunks would stay trapped on the internal filter as all has to go by this internal filter to be able to hit the cooler line... (as Bones also stated). Worn clutch fiber and trans fluid gets flushed out through those little holes in the drums (that i refered to in an earlier post) and drops to the bottom of the case. Waiting to be sucked up again through the screen for another spin. Maybe this time it will be the "some" that got to go to the cooler and external filter.

In general clutch fiber has very little problem going through domestic filter screens. Yes it's abrasive by nature and wears down pistons and seals. Maybe that is why they show more wear on their shafts and bores. at 200k km than this transmission. Or is it that this fiber residue is larger?

I say honda should have made a larger, less fine screen, and put an external filter.... Wait! isn't that what they did on the Honda Fit?

or at least some way to clean the screen every so often (a simple threaded hole in the bottom of the case which would lead to "after" the screen" .Air and cleaner would then be sent in to "reverse flush this screen"... yes i was tempted when it was all apart!

Untill then i would suggest: drop the oil in the case every oil change (~3 quarts) and do a complete flush (machine needed) every other year. And drive her easy.



My total bill? original flush (16liters dexronVI and trans cleaner/conditioning ,many cans of brake cleaner (some for original diagnosis) (also to clean dissemble trans).
2 case gaskets (20$)
3 clutch discs (3X $7)
~8l dexronVI (sorry Honda your oil is expensive and was told dexron works ok)
about 10 hours for diagnosis drop and inspection.
Now before all of you run out and expect your corner transmission shop to do this (dealers don't open transmissions?????); Keep in mind that this was a research job- under normal situations the overhaul would be replacing all seals and fibers; sending out torque for testing.

As for lockup codes- I'm assuming that the volume/pressure is dropping just enough for the converter not to be able to "hold" in a lock when comanded. the ecm/pcm "sees " excessive slip between engine rpm and input shaft rpm hence setting code.
I heard there was a TSB on converters- will readup on it
selenoid codes can be as a result of electrical or mechanical failures. Never assume without diagnosis.

PS: normal symptomes of one "worn" clutch pack on "other" brands are usually a flare/slip when going into that gear. Not slip in all gears or failure to engage.
Always follow proper diagnostic procedures before assuming that this is your problem- similar condition/symtomes may be caused by different problems/failures.

So there you have it! :_doh:
Drive her nice, change her oil often ( flush and also from her drain to evacuate coarser fiber debris), install an external filter- and hope

ME:argue:HONDA