Hi all,

My transmission has the pump whine upon startup. It shifts OK when the engine is still cold after startup. After the engine is warmed up it would slip out of gear. Any type of throttle pressure would result in a slip. I've done multiple drains with Sea Foam Trans Tune. I've also filtered out the ATF after the drains and the ATF is clear and clean. The magnet is also clean. I've checked both shift and lock solenoids. Their filters are clean, resistance good, and activates fine with 12V. The speedometer works fine so I don't think there's anything wrong with the speed sensor. The throttle cable feels fine (not loose or too tight). I am starting to think that the internal transmission filter is clogged. If it is clogged, what else can I do to clear it (without dropping the transmission)?

Thanks for your help.
Beocop

 

It's most likely impacted with clutch material.
You might be able to use small copper or brass tubing, attach it to the end of a can of brake cleaner and blast it off the filter screen via the drain port.
One fellow did drill a hole in the bottom of his case where the filter is located and was able to directly blast it clean with brake cleaner, and then sealing it with a brass plug. But I'm not a fan of drill a hole in the case.

 

That's a good idea. Do you know the screen's location relative to the drain hole? I've never looked through the drain hole because the wheel and suspension parts are in the way. An inspection camera would be nice to have.

 

It's at the other end of where the main case is bolted to the valve body/TC housing. I'll see if I can locate the thread. That poster actual did measurements and noted them down.
EDIT: BOOM!/EDIT

With the car raised and the right wheel off, even with a cheapy flashlight you can see pretty well into the drain hole.
I've thought about trying to see if I could get an engine cleaning brush to make it over to the area, but am a lazy bugger.

 

That's a great thread, Mike. I guess I never happened into it when it was going. The thing about it is that that guy had trouble in all gears. Would it make sense that if you had trouble with just one gear it's likely the clutch packs for that gear.

 

If it's all gears it's most likely lack of fluid or lack of fluid flow(impacted sump pickup, failing pump,).
If it's just one gear it could be a problem with a shift solenoid(stuck/gummed up(causing it to bleed over), clogged solenoid filter, non functional due to electrical/harness/TCU/PCM issue, including dead/dying battery or loose dirty connections(more common with newer cars that are more sensitive to electrical draws)), worn clutch pack(slipping/no engagement), or possibly a leaking internal seal/accumulator. Or even a really out of adjustment throttle valve cable at the TB(90-97 models).

With later Hondas there are other issues that can cause a slip or lack of power in a given gear as there are the clutch pressure switches, linear valves(either a solenoid issue or an adjustment), and other sorts of fun.

Best way to verify a condition is to do ye olde basics of fluid fill, cleaning, checking for solenoids clicking with an audible 'click', TV cable adjustment(90-97), and finally pressure values are correct for a given gear/rpm. I recall there was an issue with 'new/rebuilt' Linear valves/solenoids on the 98-02s as they were not properly adjusted or checked for adjustment(pressure) when installed causing slipping/prematurely worn clutches.

 

Update:

I did more drains and refills but that did not help. The fluid that came out is very clean. The transmission pump whine was still there. I decided, as a last resort, to drill the transmission case to have access to the filter (the "Tyler" method).

I originally wanted to put a M14x1.5 drain bolt in that location because it it a common size. However, I cannot locate any local store that sells a M14x1.5 tap. I did have a M12x1.25 tap and corresponding drill bit from an earlier project so I decided to use them instead. I bought a M12x1.25 oil drain bolt from Advance Auto.

Drilling the transmission case was pretty easy since it is aluminum. I used the photos in the link that Mike provided to locate the hole position of the filter (https://honda-tech.com/forums/honda-.../#post50667457). There is a slight problem with that location because it lies in a "valley" of the transmission case where the surface is not flat (Please see the photos in the link). I moved it a little further back to the nearest "flat" surface. It it further back than ideal but it's the next best location. I did two pass. The first one with a smaller bit and the second one with the actual/final size drill bit. After the first bit broke through, some more ATF came out. The second drill pass took a little longer due to the larger hole size.

After I drilling, I looked up and saw that the hole was at one far end of the filter opening. The filter material is a metal screen that has fine holes. I was expecting a lot of sludge on the filter screen but nothing came out when I tried to softly scrape the screen (the multiple drainings probably cleared the majority of gunk off). I then blasted the filter with brake cleaner. I probably used 1/2 a can. At certain times, during the spraying, more ATF would gush out. I knew then that the brake cleaner did its job as the filter screen holes were probably plugged and held ATF above them. Blasting the screen with brake cleaner cleared the screen holes, allowing the ATF above the screen to drain out. After spraying the brake cleaner, I checked to ensure that the filter screen is clean. It was hard to look through the tiny hole (~10.5 mm) but you can see enough. I then flushed the system by pouring ATF through the ATF fill hole and letting it drain out the newly-drilled drain hole. After that, I put in fresh ATF.

After starting it up, I no longer hear the pump whine. Cycling through the gear positions result in quick and positive/firm engagements (previously, it would take one/two seconds to engage Drive). The test drive was great. All gears shifts were smooth and positive. I did not observe any flare or slip. No harshness in upshift or downshift. I was so relieved.

Lesson learned: Honda should use a "servicable" filter. Having a filter that requires dropping the transmission and disassembling it to access the filter is poor engineering design. I believe that many transmissions could be saved economically and with little time/effort by putting an access/drain hole beneath the filter. You can drain the transmission and clear the filter screen at the same location. I recommend anyone having similar problems to first perform multiple drains. If that doesn't help, drill a new drain hole to clear the filter screen as described above. The new drain bolt head does protrude from the transmission block and can be prone to damage because it is the lowest point of the transmission block. I believe you can buy drain plugs that are lower profile or have heads that are flushed with the block surface.

Thank you to Tyler for discovering a practical way to service the transmission filter screen. Thank you Mike for your knowledge, advice, and willingness to help others. I hope my experience will benefit others with the same problems.

My next project would be to install a Magnefine filter. Can anyone help identify the return line and advise on the location of where to put the filter?

Thank you all.
Beocop

 

I'm so glad that you posted this Beocop. You've renewed my enthusiasm to perform the "Tyler Method". I'd lost my enthusiasm after checking everything else yesterday afternoon but stopping short of drilling my case.

Did you take any pictures of where your drilled the hole in your case and what the plug looks like after you had it installed?

Again, I really appreciate your taking time to post your outcome with the "Tyler Method".

 

I did not take any photos. I just referenced the photos from Tyler's pictures. If you use his photos, the center is 4.25" (not 4.5" like on the edited photo) from the edge of the case and 0.5" from the edge of the case reference point (please see attached photos). The problem is the center of the screen would be in a "valley" where the surface is not flat so I picked the next closest flat surface location (probably 1/3" from the center). After I drilled, the hole is at the far end of the screen.

The bolt is used looked just like Tyler's. The head protrudes from the case. If possible, try to find a bolt that will be flushed with the surface. This will reduce the chance of of damage from scraping.
Good luck.

Beocop

 

Thank you for the explanation Beocop.

One more question, did you refill with Honda ATF DW-1 or did you use something else?

-Neal

 

I used Honda DW-1.

 

IIRC the feed line is the short line next to the upper pair of solenoids, and the return line is the longer hard line that goes back towards the diff lubricating the final drive bearings. The fluid is drawn through the pump, pushed throughout the trans, comes out of the short line, is cooled, and finally lubricates the rear differential.

Trans is a low pressure unit, a couple of hoses into a drain pan and someone kicking the engine over for a moment will reveal which is the pressure side without making too much of a mess.

And as for the writeup...


... soo good.

 

It's awesome to hear of another person utilizing that idea to clear away the filter gunk. We can start referencing people to this thread as a work around instead of having to pull a tranny and crack it open.

 

Thank you again for posting your results Beocop.

I performed the "Tyler Method" on my 1991 LX lat night and had success with getting my transmission back in service.

I used a 1/2-13 set screw as my plug so that it would be flush with the bottom of the case. I used your measurements and reference points to locate my access hole. I drilled my right at the edge of the flat portion of the TC with the edge of the hole just a hair into the slope and was basically directly below the filter screen. When I peered into the hole that I made all that I could see was a gunky mess. It showed no signs of being a screen. When I started spraying the brake cleaner into the hole onto the filter screen I had the same experience as you and Tyler in that a large amount of clean ATF gushed out of the hole. I know then that the procedure was very likely going to be the answer to my problem of having no gears at all.

I flushed the TC with clean ATF to remove all of the drill and tap filings and any residual brake cleaner, put the plug in and filled the sump with fresh ATF. WHen I started the car I got a solid shift in the reverse and I was ecstatic to say the least. I drove it around a little bit and started experiencing slipping in the forward gears again. I rechecked the fluid level and found that fluid no longer registered on the dip stick so I added another 1/2 - 2/3 qt of atf and it appeared to be full again. I had already added 3 qts of ATF when I refilled the sump and the level read full on the stick. I guess with all of the draining and filling a little more than the normal drain and fill amount had been removed wfrom the tranny.

I am not driving it today because the set screw threads are not snug in the access hole and there is a little bit of ATF that leaks out around the threads and I can turn the set screw with the end of my finger. O am going to have to seal the threads of the plug using either hi-temp RFT or possibly some aircraft gasket maker if I still have some on the shelf from my VW repair days.

The "Tyler Procedure" needs to be added to the FAQ so that other will be able to find it and resolve their transmission problems. There's no telling how many transmissions have either been junked or rebuilt needlessly due to the poor design and maintenance of these transaxles.

My grandfather use to cuss and fuss saying "If they made the engineers who designed these things work on, repair and maintain the things that they designed, they would design them differently". His reference was directed specifically to the oil fill hole at the base of the crankcase of the old Briggs & Stratton vertical shaft lawnmower engines. Those of you that are old enough to remember those will know what I'm talking about.

The total cost of repair excluding replacement ATF was less than $30 for the set screw, drill bit, tap and can of CRC brake cleaner. All-in-all a very good deal considering no dropping of the transmission or expense of a used or rebuilt unit.

 

I am glad it worked out for both of us. Regarding your leak, maybe you could try using a drain plug that has a low profile head where you can still use a washer to stop the leak (see attached photo).

 

Thanks Beocop. I like the look of that. Where would I look for something like your picture?

 

It is basically a drain plug. Many manufacturer make plugs of different size/shapes. You can first try to search for images using the terms such as: "oil drain plug", "transmission drain plug", "oxygen sensor plug", or "differential drain plug". That basic low profile shape with the inset hex key is common in differential drain plugs. Finding the correct size can be a problem if your hole has an uncommon size and pitch. For me, finding the one that fits a M12x1.25 profile is hard. However, I found that there is an oxygen sensor plug with M12x1.25 profile that has the similar head profile that might work for me.

 

I got to searching around and found a low profile oversize oil drain plug with a gasket that is 1/2-20 and that is just a hair larger than 1/2-13 so I think I'm going to go with that. It's available locally at the auto parts store for less than $4. think that I can just gently turn it in and be done with it.

 

What you can do is to clean the hole area real good with brake cleaner, then yeah, hit the plug threads with some rtv . They do the same thing to engine block plugs.

I totally agree we need to get this thing stickied and more and more people to learn about this method. I think calling it the "Tyler Method" would be a great tribute to the guy that got it started.

 

Changed my mind. Since I had drilled my hole a little further over than Tyler and Beocop I surmised that using a flat bottomed drain plug and gasket may still leak a bit. Therefore, I kept my 1/2-13 set screw and used Permatex Aircraft Form-A-Gasket to seal the threads. The Form-A Gasket is impervious to oil and grease and will withstand temperatures to 500 degrees F. It will also tolerate a small bit of oil on the surface that is being sealed. So far the plan looks like a good one. I'll post again in a few days and let everyone know if the seal is holding.

The Aircraft Form-A-Gasket did not seal. I ended up using black high temp RTV on the threads of the plug and it sealed nicely.

 

Glad to see this is working!
The introduction of brake cleaner would make me nervous since even a small amount can break down a large amount of oil. I'd add a recommendation of buying at least 4 or 5 quarts of cheap universal tranny fluid and running all of that through it before starting the vehicle and possibly introducing the brake cleaner into the torque converter and contaminating the tranny fluid in there.

We had a new lube tech take a hand pump from our cleaning solution drum and put it in a brand new 55 gallon drum of Kendall oil. Just the residual cleaner from the pump was enough to breakdown all the oil in the drum. We actually had an oil analysis completed on the oil out of curiousity.

 

I wanted to ask if this thread can please be stickied ? Maybe also change the title to something to the effect of how this is a possible fix for a clogged internal atf filter.

This is probably the best thread to not be stickied and can work to help people who can't afford an atf rebuild due to a clogged internal filter but are good enough to do the fix.

 

https://honda-tech.com/forums/honda-.../#post50667457

Also that thread, which is directly tied to this one and referenced by Mike in page 1 of this thread. They should both be stickied.

 

The "Tyler" method worked for me.
Used a M12x1.25 tap and M12x1.25 bolt from Advance and a 27/64" drill bit. The bolt from Advance also came with a washer.
Once I finished there was no leaking from the bolt. Drove it about 50 miles and the whine is gone upon startup and no disengaging of the gears.
If you try to use a different bolt/tap, here is a handy chart:

 

@djkurious would you mind linking, or giving the part number for the bolt you bought?

Also, this might be an idiotc question, but would compressed air be a possible replacement for the brake cleaner? The we wouldn't be worried about the chemical properties of brake cleaner.