The mysterious Honda AT?

[JTK]

Being totally new to Honda automobiles, I'm intrigued by the mystery surrounding Honda automatic transmissions. I've yet to find any information about them online, etc. From what I've read, years ago, Honda wanted to go it alone and not infringe upon anyone's AT patent. Thus the development of the Honda AT without planetary gear sets. Apparently Honda AT's use conventional sliding gear sets like that of a manual transmission. The 5spd AT in my new Odyssey is definitely different looking than what I'm used to. Sort of compact, no bottom pan, a top fill plug, a bottom drain plug and a dipstick. From the one or two pics I've seen, they also have an odd looking torque converter and what appears to be some 'motors' protruding from the case. You even check ATF level with the engine off?! That's a first. I'm aware of the trans issues Honda had with the Odyssey. Apparently there was a lubrication problem causing overheated gears and burnt ATF and maybe some other durability concerns. Word on the streets is, Honda now uses the “4-shaft” (what ever that means) heavier-duty trans from the Ridgeline in the Ody vans. At least with Jatco, Aisin-Warner, GM, etc, there's LOTS of info to be had. What gives with Honda? There's millions of them out there! Anyone have any links?

Thanks
Joel

 

[The Critic]

What would you like to know?

Perhaps you could consult the factory service manual?

 

[Squishy]

This piques my interest. Check it with the engine off you say? I don't remember reading that in the manual.

Time to check again

Oh, and the reason for the transmission failures, based on the MDX recall (which I think uses the same transmission as the Odyssey), is because of second gear not receiving enough lubrication. The stupid recall installed an oil jet to spray transmission fluid directly onto the gears - problem was that the jet was installed in place of the fill hole. Now it takes half an hour to fill the dang transmission using a fluid pump through the dipstick tube with a ridiculously thin hose.

 

[JTK]

Just curious to see if Honda had a site I'm missing. Maybe some specs, cut-away views, is there a serviceable filter? etc.. No need for a FSM seeing as I'll be giving the van back in 3yrs/36Kmi.

Joel

 

[Squishy]

Hey you're right, we're supposed to check with the engine off. I've been doing it wrong for the last seven years!

How deep do you want to go? I have material on the 2005 Odyssey transmission that goes pretty deep, from general operation to clutch operation, hydraulic controls, electronic controls, etc.

And no, there is no "serviceable" filter, just a metal screen that's buried behind the valve body.

 

[CharBaby]

My 1988 Accord ATF was checked with the engine off as well and that was 20 years ago.

 

[JTK]

Originally Posted By: Squishy
... I have material on the 2005 Odyssey transmission that goes pretty deep, from general operation to clutch operation, hydraulic controls, electronic controls, etc.

And no, there is no "serviceable" filter, just a metal screen that's buried behind the valve body.


Thanks Squishy and Critic. I don't want to trouble you guys. I was curious to see if any online sources existed. I have a basic understanding of 'conventional' automatics, but Honda has me puzzled.

Joel

 

[Squishy]

Once I post it, it becomes an "online source."

I have seven articles on the 2005 transmission's operation - if you can confirm that the 2008 uses the same thing, I'll start posting them. I also have overhaul instructions, but they're a little long-winded to post. If you ever need to take it apart, just PM me and I'll see if I can create a PDF.

 

[Jon]

The "drive accord" website has a very good description of how Honda ATs are fundamentally different from other autos. It grumps me that some companies are all in the news about dual-clutch stuff and Honda has used dual clutch for practically forever. Essentially, Honda ATs are manual transmissions that are electromechanically shifted, which gives them manual-transmission-like economy and shift characteristics. Great for when you have your foot in them but the extended slipping that Honda added in more recent years (read: after 1996?) resulted in a reduction in reliability due to increased heat and wear. The older transmissions shifted harshly (esp. 1992-ish) but were rock-solid.

I'm faulting Honda for what I think are a bunch of bone-headed decisions combined with cutting-edge technology. Honda seems an odd mix of "really awesome tech and perfect this and that" combined with "bone headed decisions". Case in point: the cruise control on my '02 Accord is vacuum driven (electronically but vacuum driven) and has NEVER WORKED WORTH A DARN in the cold. Not putting a knock sensor in until '03 was also bone-headed IMO - the timing has to be so conservative that it results in lowered efficiency and power. Grr.

 

[JTK]

Originally Posted By: Jon
...Honda has used dual clutch for practically forever. Essentially, Honda ATs are manual transmissions that are electromechanically shifted, which gives them manual-transmission-like economy and shift characteristics...


That's exactly the type of layman stuff I was looking for. Thanks Jon. Some other cool info I dug up (I know some has been covered before)is the Odyssey 5spd ATs from 1999+ all have an external filter. 1999-2004 use a cannister sytle, similar to a big fuel filter, mounted on top of the trans case. 2005-2006 use a 'drop-in' style, mounted horizontally, in the same spot on top of the case as the 1999+ and the 2007+ use a drop-in element that mounts near the dipstick tube on the towards the input end of the trans. Part #1 here:
http://www.slhondaparts.com/images/PCI/14SHJ5/003/2.jpg

Joel