Why do some transmissions use filters and others don't?

[shertex]

Just curious. Value of a filter is obvious enough. But some trannies, e.g. my Honda Odyssey, don't use a filter. Why not, if it's so important? On the Odyssey, the drain plug is magnetic, so it attracts the metal debris. But not really much on there, even after 45,000 miles (I did a few drain and fills with a topsider in between).

EDIT: My 02 Odyssey may have a filter, but replacing it is certainly not part of the scheduled maintenance.....not really accessible.

[vstech]

I was not aware of any automatic transmissions without a filter...
the odyssey apparently does not need one, however, it's more likely that it's a dealer only part.

[vstech]

... 02 odyssey filter... available here on fastlane.

[shertex]

Originally Posted by vstech

I was not aware of any automatic transmissions without a filter...
the odyssey apparently does not need one, however, it's more likely that it's a dealer only part.

I guess my Odyssey much have one....odd that occasional replacement wouldn't be part of the regimen.

[shertex]

Originally Posted by vstech

... 02 odyssey filter... available here on fastlane.

Thanks. Ominous note: "This filter is not replaceable during normal maintenance. Replacement of this filter requires removal and disassembly of the transmission."

[vstech]

yup. certified mechanic, or dealer installed part no doubt... scary.
is it a cvt trans?

[sixto]

My 98 Camry had a mesh that was cleaned when the pan was dropped. There was no stated interval to drop the pan. ATF service consisted of replacing the 4-5 quarts that drained through the hole in the pan. Refill and go.

They must figure transmissions don't fail in a small way. If there are chunks a filter would catch, the transmission needs to be rebuilt or replaced. On the plus side it reduces maintenance cost for the first owner. That's a plus for people whose ownership ends when the warranty expires.

Sixto
87 300D

[compu_85]

The olde 3 speed VW transmissions don't have a filter either, just a screen.

[sixto]

They don't even have engine oil filters, just a screen

Sixto
87 300D

[engatwork]

"This filter is not replaceable during normal maintenance. Replacement of this filter requires removal and disassembly of the transmission."

I think there are quite a few Hondas like that. The only way to change the filter is to disassemble the tranny.

[shertex]

So if all transmissions have filters, but some have filters that, as a practical matter are NEVER going to be changed, what accounts for the differences? Is the tranny on my Odyssey, as an example, unusually robust by design (even though it failed at 40,000 miles, but that's another story)? Are recommended filter replacement intervals overly cautious? Or are typical filters unusually flimsy (compared to filters that are inaccessible)?

[engatwork]

My experience with the Hondas have been good. In an earlier life we had a 97 CRV that had ~250k miles on it when the oldest son took out a brick mail box with it. I had replaced the fluid in it every 30k miles. Never had a bit of problem with it. I just recently changed the fluid/filter in a 2005 BMW 325Ci (GM transmission with ~64k miles) and the fluid was pretty nasty. It does have a pretty innovative, fool proof way of filling it. I'm doing the fluid/filter in a 05 Crown Vic today. I try not to let ppl know I work on Fords or Chebbys.

[compu_85]

Originally Posted by sixto

They don't even have engine oil filters, just a screen

Sixto
87 300D

Yup, the aircooled's don't have a filter either. But VW used that transmission until 1993 on some models so the screen lived on

[sixto]

Along that line, why does MB use a power steering filter when no one else does?

Sixto
87 300D

[compu_85]

Because power steering fluid never needs to be changed... so why put a filter on it?



Just like that lifetime transmission fluid...

Do modern MB's still have the power steering filter?

-J