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Hello all, I am an ASE technician. If you have a tranny issu such as slipping or hard shifting chances are it's just 1 or three pressure switches/sensors. I recently had an Odyssey come in with all engine lights on and would not shift into 2nd gear. I replaced the 3rd clutch switch $80 and now it runs like new. Trust me on this, us mechanics are trained to lie cheat and steal. Never replace a tranny in a honda unless all 3 switches have been checked or replaced. 3 times now that has been the issue. I even took an old tranny that was replaced and it also just needed an $80 pressure switch. Shops are robbing you guys out there. Oh yeah and it's so easy to replace a child could do it. One is under the batt. box (2-3 gear shift switch) and takes 10 mins to change. There are 2 more on the top of the tranny kinda close to the dip stick hole.
 

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A few days ago I had trouble with my 2003 Odyssey. Stopped at car wash, couldn't put it in gear to pull into bay. I couldnt even move shift arm into drive position, only reverseand park but even in reverse it didnt ctually reverse. Put it in park & shut off, then tried again and it worked fine. Honda service said it was my transmission, bits of clutch pad were getting into fluid and plugging transmission lines, $6k to replace transmission. Do you think it could really be switches? Any way to test without replacing switches?
 

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OP, I get where you are coming from. But what you say doesn't make sense. It is true and might be for some cases but Honda replaced thousands of trannies on their dime. I would think Honda is not stupid enough to just swap out trannies and pay for all the work (warranty, good-will and voluntary warranty extensions). I agree with you that in some cases, it might be the pressure switches but there are threads on here where people did swap out the switches but eventually, the clutch packs were so damaged that the people did need new trannies.

I personally have gotten 2 trannies both free. I doubt if it was just the switches, Honda would have spent so much to swap out the 2 trannies in my Accord.
 

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The switches wouldn't be bad if they weren't all choked up with the disintegrating disc's.
 

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The switches wouldn't be bad if they weren't all choked up with the disintegrating disc's.
It's hard to say; it's the old chicken-and-egg situation. Something has to happen first to cause the clutch discs to slip & fail (which then causes debris in the oil). Bad pressure switches which cause two gears to be simultaneously applied, or allow excessive slippage (heat > burnt clutch discs) to occur in one clutch pack, could very well be the root cause.

Certainly, debris that clogs solenoid valve screens and other hydraulic passages contributes to the downward spiral of internal failure. But something has to cause the debris in the first place.
 

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It's hard to say; it's the old chicken-and-egg situation. Something has to happen first to cause the clutch discs to slip & fail (which then causes debris in the oil). Bad pressure switches which cause two gears to be simultaneously applied, or allow excessive slippage (heat > burnt clutch discs) to occur in one clutch pack, could very well be the root cause.

Certainly, debris that clogs solenoid valve screens and other hydraulic passages contributes to the downward spiral of internal failure. But something has to cause the debris in the first place(My emphasis via underscore & italics.
red, I believe you've got it.

The "chicken" in this is a number of engineering issues per the NHTSA report on the 3.2TL trannies (same as our 3.5 V6 BYBA code in the 2nd gen 5-spd Odys):
1.) A spring that can be "timed" so as to block one of the ports feeding ATF to 3rd clutch pack (for cooling, and wetting the plates for proper friction characteristics).
2.) Mis-timed port plug that can also limit ATF flow to 3rd clutch pack.
3.) Out-of-spec friction on 3rd clutch steels (as in, too much surface roughness).

The first two yield quite a drop in the amount of ATF flow into the 3rd clutch pack. There's always enough to wet the plates as long as the sump was properly filled in the first place, so 3rd clutch plate wetting (or lack of) is not the problem.

This gives us our primary problem of not enough ATF for 3rd clutch heat exchange.

"The egg" is the result of localized temperatures in the 3rd clutch exceeding 300-deg Celsius and the resulting accelerated 3rd clutch friction thermal degradation. The higher temperatures make for a ripe environment to help the somewhat-rougher-than-expected 3rd clutch steels (secondary problem) to wear the 3rd clutch frictions in an even faster manner.

The "spiral" you mention is documented, whereby ATF contaminants (3rd clutch debris) clogs screens and negatively affect hydraulic fluid power circuits and solenoid operated valving, which can lead to more wear, more problems with affected items, more wear....our own Wade Chamberlain noted that his own 2nd Gen 5-spd DIY tranny rebuild resulted in removing a 3rd clutch pack that was almost completely devoid of all clutch friction material...the other clutches did not have this degree of damage. I've seen more than a few web forums with pictures of the 3rd clutch frictions...they looked more like steels, since all the friction material was gone. All of it.

I think William Wiles also nails it down: "The switches wouldn't be bad if they weren't all choked up with the disintegrating disc's."

I will admit that some of our 2nd-gen Ody members have replaced switches and solenoid-operated valving and achieved the success of an operating tranny, but relative to the sheer numbers of replaced trannies, sadly they're in a very small minority.

I follow the results RinconVTR generously provided. He paid for two consecutive Blackstone UOA's on his ATF. The conclusion he arrived at from Blackstone's data was that 15,000 miles was about all one could expect with Honda ATF before having to do a single drain-refill to refresh the ATF's additives package, dilute contaminants, and prevent the viscosity from degrading to an unacceptable level. This is on his 2009 Ody with the 4-shaft tranny and lighter duty driving (I read that he had no or very little severe service during his second ATF change interval).

If you do more than this, like tow, or run up and down mountain passes, and/or have the 3-shaft tranny with its internal flow issues, 10,000 miles might be a better choice, or even with each oil change.

I just drop the sump load of ATF when I do an oil change, and refill it (my OCI is 10,000 miles with Mobil 1 5W20 and an AmSOil EaO44 filter). I use AmSOil ATF in both Odys now. Don't know if our two Odys' trannies will turn into bombs. Just keeping my fingers crossed, and keep driving them. What else can I do?...other than replace the undersized OEM coolers with better units. With 4 kids, I just don't have time for this. I just did the front & rear brakes on both Odys, for crying out loud, and now have a pair of timing belt changes to do.

Even then, after reading the NHTSA report, I'm no longer confident that doing frequent ATF changes is a 100% solution for long and happy transmission life. If you have a BYBA-coded 2nd gen 5-speed tranny (prior to late 2004 model where Honda made engineering drawing changes to address the 3rd clutch ATF flow issues), and you have the combination of negative items (spring covering port due to timing, and port plug timed to also reduce ATF flow), you will end up with the 3rd clutch high ATF temp conditions which can wreck the 3rd clutch. A supersized ATF cooler (bigger than the OEM finned drinking straw) seems to be a helpful answer, along with more filtration.

I should have purchased stock in Emergent Technologies, the makers of the Magnefine filter, when bbylon5 posted his installation on his DIY ATF cooling circuit. Got one on each of my Odys as well.

Mind you, when our vehicles were assembled, the techs installing these pieces (which fell under Honda and NHTSA scrutiny in the report) were not doing anything wrong...it's just the way those items were oriented on assembly that appear to cause our problems with 2nd Gen trannies. If they assembled them such that ATF flow into the 3rd clutch was not impeded, you might be one of those original-tranny-guys posting on the 2nd Gen 200,000-mile thread.

On a side-note, it also does seem that a larger-than-expected number of 3rd Gen owners are having problems with torque converters and other tranny issues. Doesn't seem to be any end to this stuff.

Just got to quit worrying about this stuff. There's a dose of Smirnoff waiting for me when I get home tonight.

OF
 

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Dang it OF, you mentioned everyone but herrhaus and I. :(

Seriously though, you do type very long well thought out responses. :)
 

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"If you do more than this, like tow, or run up and down mountain passes, and/or have the 3-shaft tranny with its internal flow issues, 10,000 miles might be a better choice, or even with each oil change."

Did the 10k ATF Z1 only changes for yrs. Failed anyway. Can not tell if failure came later than with maintenance at owners manual rec intervals of 30k-45K mi. It still failed. Are 5000 mile ATF changes better? I have no documentation either way.

Some owners who changed screens, switches still had failures. Some have not reported back. Did they fail too?

Maybe the geniuses who designed Honda transmissions would know if 5000 mile, 4000, 3000, 2000, 1000, 500, 50, or 1 mile transmission fluid changes help. But they certainly did not know how to design transmissions or they cut some corners at the owners' expen$$$e.

I hear you about Smirnoff or your beverage of choice.
 

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My apologies to dvpatel (who's been through some real tranny woes) and herrhaus (cooler installer, and documentor of screen & filter tube cleaning)! :redface:

I am long winded. I should just look for the links to this stuff and post it. :(

Thinking about buying a junkyard tranny and doing a DIY rebuild like Wade did, but who has the time? I sure don't.

Yeah, buildit...just going to keep driving it until it quits. I can't eat gluten, so stuff from fermented corn (or non-wheat stuff, like potatoes or grapes for other vodkas) is the only choice I've got these days. No more crying into a beer for this guy, just crying over not being able to have one :cry: (and preparing to weep if I have a tranny disaster).

OF
 
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