Honda Odyssey A/T "Boil Over"

Winston · Sep 5, 2005

So I was going camping this weekend. I have a lowly '95 Mitsu Montero pulling a tent trailer and I was following my friend with his '02 Honda Odyssey pulling a tent trailer. We were cruising up Highway 5 goin' 65mph with 87deg ambient temperature when some nice black smoke started pouring out from his minivan. We pulled over and sure enough the ATF had spilled out of the tranny dip stick. It smelled all burned. And my friend said that the transmission had started slipping. After it cooled down everything worked OK and we made it to our destination and home again. (travelling a bit slower).

I know that this is a typical scenario when transmission fluid overheats, but I have a couple questions.

1. Why does the fluid get so hot? What generates the heat? I assume the Odyssey has a lock-up torque converter, so what process in the transmission generates heat when you are cruising on the highway?

2. How hot does the fluid actually get in this situation? Is it actually boiling? Or what causes this extreme expansion of the fluid which causes it to come out of the dip stick.

And yes, he is getting his tranny fluid flushed today. He had a tranny fluid cooler installed by AAMCO ($300 vs the $600 dealer cooler - might have been a false savings). Anyone try the AMSOIL ATF in their Odyssey?

Winston · Sep 5, 2005

Just to clarify. He had the cooler installed before pulling the trailer. The trailer is within the rated pulling capacity of the van. When he went to AAMCO he told them the weight and type of trailer and they looked on some chart to determine the cooler size.

As far as the heat. We had been driving for approx. 1 hour at a steady 60-65 maybe 68mph speed. The Odyssey has a pretty powerfull engine (240hp) I am certain it was not shifting during this time. My truck is underpowered (170hp) and my trailer is bigger. However, I know I have a lock-up torque converter. My truck does not downshift under these conditions, so I am sure his did not either. The only source of heat I can figure is torque converter slippage. Maybe his Odyssey does not have a lock-up torque converter.

He does not know if AAMCO topped up the fluid.

Ray H · Sep 5, 2005

If AAMCO changed the fluid at the time the cooler was installed, it's likely they refilled with Dexron III and their version of Lubegard black instead of Honda Z-1 ATF. His service receipt should show whether the fluid was changed out. He may have a claim against AAMCO.

MolaKule · Sep 5, 2005

AAMCO could have overfilled OR underfilled and both lead to boiling.

Sounds like his TC wasn't locking or being locked up.

Good idea having the fluid changed before a trip and in this case, having it now replaced since it is most likely oxidized (shot).

Make sure AAMCO has the cooler up front of the radiator and if the cooler has a thermostat on it, have it checked.

Winston · Sep 6, 2005

quote:

likely they refilled with Dexron III and their version of Lubegard black instead of Honda Z-1 ATF

I was wondering what type of fluid AAMCO might have put in there.

quote:

AAMCO could have overfilled OR underfilled and both lead to boiling.

His transmission level is to be checked with the car off and transmission at operating temp. After it got to the normal temperature the level was OK, however it really stunk. Also he definately noticed that the transmission was slipping. So I do not think the only problem was too much fluid.

quote:

Make sure AAMCO has the cooler up front of the radiator and if the cooler has a thermostat on it, have it checked.

The cooler was mounted in front of the radiator. (you can see it through the grill). I saw the hoses that lead to the tranny (I was checking for leaks) and I did not see any thermostat.

MolaKule · Sep 6, 2005

When was the last time your friend had his AT fluid changed (at what mileage)?

What is current mileage.

If his fluid was original, his friction modifiers had gone a long time ago.

Winston · Sep 6, 2005

quote:

If his fluid was original, his friction modifiers had gone a long time ago.

Really?!?! I did not know that they get used up. (not that I know much of anything specifically about friction modifiers) How is it that some trannys go over 100k miles with the original fluid?

I will ask him again about the tranny fluid change. I see that Honda Minivans are supposed to have their fluid changed at 30k miles. I also see that Honda Minivan transmissions tend to fail at about 50k.

caremd99 · Sep 6, 2005

quote:

Originally posted by Winston:
Anyone try the AMSOIL ATF in their Odyssey?

Yes and I towed 3200 lbs (Trailmanor 3023) for 3 seasons. I just changed it two weeks ago at 45K and it was only a bit darker than new when I flushed the system at 10K. I changed at 10K beause I noticed the Honda fluid had changed to a peach color after one of our towing trips from VA to PA back to VA.

Winston · Sep 6, 2005

Carem,

Did you put in an oil cooler? I so, what type and size? Did you put in the Honda OEM cooler?

What about the power steering cooler? Honda recommends a cooler for the power steering fluid too. I have no idea why that would be necessary.

What year is your Odyssey.

Oh, and what color is the OEM Honda fluid?

Thanks

thrace · Sep 6, 2005

Some questions. Does the ATF flow from the cooler at the bottom of the radiator and then to the AAMCO installed cooler and then return to the transmission? Are the ATF lines kinked? Is something blocking the air to the ATF cooler or radiator? Did the trailer have a very high wind resistance and cause the vehicle to strain even if within weight limits? Was the antifreeze temp high?

If all these issues are normal, I would wonder whether it is good enough to be a tow vehicle.

Note: The 2002 Odyssey definitely has a lock up torque converter. You can manually shift from Drive, which should be 5th gear when above 50mph, to 3rd gear but cannot select 4th gear manually in the 2002 Odyssey. Maybe the trans would be cooler running in 3rd gear but the engine would be revving high at 65mph.

I hope he has the extended warranty and it is still in effect. He may need it soon. The Honda 5spd. auto has an increasing habit of breaking down. The Acura TL and CL were the worst but the Odyssey, and MDX are involved.

thrace · Sep 6, 2005

quote:

What about the power steering cooler? Honda recommends a cooler for the power steering fluid too. I have no idea why that would be necessary.

Install it now. The dealer will probably NOT repair the transmission under warranty if the ATF cooler and the PS cooler are not installed. Trans repair cost $4000-$5000 from the owner's pocket. These are required for trailer towing. I really do not know why the PS cooler is needed however underhood temps are high in towing and one cooler more may prevent PS problems. Go to an online Honda parts store such as San Leandro Honda or hondaparts4you.com and buy it online and install it.

Original Honda ATF Z1 is pink just like any other brand ATF and is "petroleum oil", not synthetic.

MolaKule · Sep 6, 2005

When pulling any load, always use or have an ATF cooler installed and use the next lower gear to avoid upshifts and downshifts.

Friction, actuator motion due top shifting, torque converter slip, and insufficient cooling are causes of ATF boiling. All fluids expand when heated, ATF more so.

No false savings with the tranny cooler, just common sense. Should have installed it before trailering.

White 03 · Sep 6, 2005

Good questions, I don't know either but would like to know.

A couple other questions more about the Odyssey: Is the trailer weight more than the cars rated ability?

Could it be the transmission wasn't locking but should have been?

Also from what I have read Honda transmissions seem to do best with Honda fluid, is that what was in the Odyssey? What fluid did AAMCO use?

From what I have seen AFT does seem to expand when hot; I am not sure if it could be more than motor oil but the results seem to be overflow.

I have seen temps up to 200 degrees and have read of them to 300. Some where in that range it seems the oil goes bad and damage is caused or at least the oil goes bad and needs replacing.

I hope we get more replys.

On edit: Mola got in while I was composing; thanks for the insight. I thought the ATF expanded more but couldn't figure why as it is mostly just oil.

Also, I was reading it as the cooler was installed, if not then maybe he was pushing it.

Ray H · Sep 6, 2005

Do a search here on Honda ATs - some model year Hondas' automatics were/are subject to a warranty extension Honda issued for internal modification and repair if second gear is darkened/discolored from excessive heat upon inspection.

caremd99 · Sep 7, 2005

quote:

Originally posted by Winston:
Carem,

Did you put in an oil cooler? I so, what type and size? Did you put in the Honda OEM cooler?

What about the power steering cooler? Honda recommends a cooler for the power steering fluid too. I have no idea why that would be necessary.

What year is your Odyssey.

Oh, and what color is the OEM Honda fluid?

Thanks

2002 EXL. I used the overpriced Honda Power steering cooler because I didn't know any better at the time that I could just use a small trans oil cooler. I used a True Cool 4452 orginally with the OEM trans fluid because the Honda cooler is very expensive and doesn't seem to have much capacity. When the OEM fluid turned peach after my trip I added a True Cool 4454 in series with the 4452. Probably should have removed the 4452 but everything has worked fine for a few years now and there have been no leaks.

Winston · Sep 12, 2005

So, I followed up with my friend today. He confirmed that the fluid has never been changed. I had mentioned that he should at least get the fluid changed and he said he was going to take it back to AAMCO to see what they said. Here is their response;

-They topped up the fluid and said it was fine.
-The AT cooler was fine too and is rated to tow up to 22,500lbs

-They don't know why it overheated and said he should bring it back if it overheats again.

Well all I can say to that is a big

to AAMCO for saving him that money on the fluid flush that I recommended.

After all, they are the "experts."

unDummy · Sep 16, 2005

Those "experts" make their living rebuilding transmissions. They always seem to avoid "upgrades" and "preventive maintenance" whenever possible.

And, remember that its your friends tranny. Don't bring it up anymore. You did your best and if it fails, let it be the owners fault!

Honda Odyssey A/T "Boil Over"

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