Lifetime ATF filter?!?

Subaru says that the automatic transmission fluid filter is a lifetime part; never needs replacement (per the owner's manual).  Car is a 2006 Outback XT with the 5AT and ~130,000 miles.  I'm preparing to replace the oil line hoses to and from the filter housing as one of them appears to be leaking.  It should, "theoretically," be real easy to replace the filter while I have the battery and headlight out.  Car is a long-term hold; I'd like to get at least an additional five years and 40,000 miles out of it.  I would use an OEM filter.

What says the hive: replace it or leave it?

Yep they will last until the trans blows up and that then defines lifetime.  My Jag had this and then I got ahold of the dealer service manual not the one that you get when you purchase the car and it states lifetime for those but in fine print it said that cars that are subject to sever duties conditions should be changed every 40K.  Further reading of there definition of sever duties and it basically meant that anything that involved actually driving the vehicle basically qualified.  Is it a ZF trans?

In reply to dean1484 :

I do not know who manufactured tha transmission and I can't find that info online.

Since you're in there, I would replace.  

I was thinking 'lifetime' means until no life no more.  You don't want that.

Lots of GMs don't even have a replaceable transmission filter these days. I think the trucks are the only ones anymore.

Many cars have a filter that is servicible only by disassembling the trans.  Don't backflush, just do a fluid swap. 

Transmissions don't create debris that a filter should catch until replacing the filter isn't going to fix it anyway. So.... lifetime part.

Vigo said:

Transmissions don't create debris that a filter should catch until replacing the filter isn't going to fix it anyway. So.... lifetime part.

I've changed the filter on at least a half dozen inoperable and/or slipping trans that started working fine after the filter was changed. Chrysler trans used to be bad for this.

A number of first GEN Honda fit owners (including myself) were told the same thing. And then we learned where the part was, how to replace it, and what transmission fluid to upgrade to. A marked improvement was made and now everybody changes it at every about 30 to 50,000 miles.

I've changed the filter on at least a half dozen inoperable and/or slipping trans that started working fine after the filter was changed. Chrysler trans used to be bad for this.

I mean this in a completely benign way but that is the literal definition of a patch job. Transmission filters by and large are pretty 'loose' and are only there to keep things big enough to damage the pump from getting into the pump. It is sort of analogous to replacing the oil pickup screen in an engine or the fuel pump strainer  in a fuel system. If either one is clogging up, it's because there's something in there that shouldn't be in there, not 'maintenance'. I suppose the distinction between 'extending the life of a failing part' and 'maintenance' is ultimately a line in the sand, though. Transmission filters won't clog up until something is seriously wrong with the trans. At that point, replacing the filter doesn't really address the problem, it's more of a punt. 

I've seen some trans filters that are fine enough to catch quite a bit of clutch sludge over time.  I could see that eventually restricting fluid flow and causing some issues.  And even a healthy auto will shed some amount of clutch material over time. 

I snapped a quick pic while replacing the trans filter on my '05 Legacy GT w/ 5EAT. Just over 100k miles and there was a fair amount of sludge and glittery E36 M3. Too cheap and easy to skip, even if it might be pointless...

Vigo said:

I've changed the filter on at least a half dozen inoperable and/or slipping trans that started working fine after the filter was changed. Chrysler trans used to be bad for this.

I mean this in a completely benign way but that is the literal definition of a patch job.

Not to pick nits, but the literal definition of a patch job would involve me actually putting a patch on something and I didn't.

Yes they were fine filters plugged with particulate, not a screen/mesh types.