External transmission filter info

[coldfusion21]

Looking for info on the external transmission filter that was retrofitted on the early legacy's. I would like to replace it with a spin on filter of some sort and dont really know where to start. I guess i can go talk to the local hydraulic shop but not sure if they will know much about fluid systems for cars. Mostly looking for flow, pressure and micron ratings.

 

Local autoparts place can get me a Wix one but its nearly 50 dollars. I can buy a spin on adapter and some fittings for that price. Will be installing a small cooler at the same time, is there any kind of thermostat currently in the system?

 

 

Thanks guys.

[idosubaru]

i don't believe they have any temp gauges for the trans/fluid. some 4EAT's (maybe all?) circuits do use temperature input to prevent the trans from going into 4th until it warms up in very cold conditions. but that's probably more of a switch than it is a temp gauge for the fluid.

 

are you looking to upgrade an existing set up or starting from scratch on a stock trans?

 

there are "remote transmission filter kits" you can buy to add on a screw on filter to any vehicle. they can include temperature gauges too.

 

if you're installing a gauge i'd do that first and keep an eye on readings before getting a cooler.

 

trans coolers aren't an item where "more is better". the trans is designed to perform at a certain fluid operating temperature, there is no value (arguably it's bad) to reduce the fluid temps below that. that's good to know even if you've already decided to get one - as Subaru's should use the smallest coolers they sell - those are orders of magnitudes more efficient than the stock set up at dissipating heat.

[svxpert]

<<I would like to replace it with a spin on filter of some sort and dont really know where to start.>>

 

why?

[coldfusion21]

Well, as i explained the external filter is a 50 dollar part. Its specific to the car. I should be able to use a oil or hydraulic filter that is super common and way easier to change while being several times cheaper. I think the filter should be changed on my car, but if i can upgrade to a spin on for the same or less money is seems like a good idea.

 

Why not?

 

 

I don't have a gauge currently, but would make provisions for one if i add a cooler and filter setup. That is why i was asking about the thermostat as some cars have one plumbed into the stock system. If that were the case i would get a decent sized cooler and let the thermostat do the work. Possibly i can locate a aftermarket one as i understand fluid that is to cold is just as bad as hot fluid.

 

This a stock system and tranny right now. No problems currently but the fluid surely needs to be changed. Who knows when the filter was last replaced. I just see an opportunity for improvement and wanna see if other people have done the same.

 

Thoughts? I'm sure someone has hooked a tranny temp guage up to a 4EAT before, did they see any reason to add a cooler?

Edited December 28, 2009 by coldfusion21

[idosubaru]

Sounds like a good idea. I'd probably do the same thing. You don't think there's a cheaper filter alternative somewhere? $50 is rather nuts for a filter.

 

I'd go with an adapter. In 1998 Subaru added a screw on external filter to their auto trans maybe you could get an adapter and use those, they would be the specifications and such that you would want for your 4EAT. Very little difference between yours and a 98+ 4EAT from a functional standpoint. That's what I would do.

 

I haven't heard of anyone checking trans temps except maybe twice but i don't recall any results. I have one of those laser temp guns guess i could check.

 

Subaru doesn't design them to run hotter than they're supposed to. If yours was too hot it would point to something being wrong, not just insufficient cooling. Subaru auto trans are very robust so the system is designed well. Failure is usually attributable to poor maintenance - infrequent fluid changes, tire rotation, getting towed, etc.

 

Now if you're towing or doing some high capacity work that might be different. But that's rare for folks to be towing that much.

[svxpert]

<<Well, as i explained the external filter is a 50 dollar part. Its specific to the car. I should be able to use a oil or hydraulic filter that is super common and way easier to change while being several times cheaper. I think the filter should be changed on my car, but if i can upgrade to a spin on for the same or less money is seems like a good idea. >>

 

i read the part for the WIX brand filter being $50 did you look to see how much a subaru one was? i had 5 of these ones last year i was selling, here is a pic of the subaru one:

 

[bulwnkl]

The Subaru spin-ons aren't cheap themselves. ~$30-35 at the local dealer here, IIRC? Anyway, according to Amsoil (FWIW), you can use one of their spin-on oil filters in place of the stock Subie spin-on A/T filter. Those have gone _way_ up in price the last year or two as well, but they're still somewhere around $15-17, IIRC? They have a bypass valve in them, just as most any (engine) oil filter does, which is either not present in Subaru's tranny filter, or else it's a very different pressure differential setting (I can't recall whether there was one in the last Subie tranny filter I took off or not). I put an Amsoil on my tranny anyway, because, whether I like their marketing or not, Amsoil has proven to be pretty darned good about actual field testing of their products, and pulling their recommendations if they detect a potential problem.

 

**EDIT: I have no idea what the Subaru OEM transmission filter efficiency ratings are, nor do I believe that anyone who has that actual information direct from FHI will share it. Still, if you obtain that info, please share here!

[Legacy777]

You can buy the whole external filter kit for like $20, which includes the filter. Yes, I know it's cheaper than buying just the filter. Go figure. That's what I did when I replaced the filter, just bought a whole kit.

 

BTW, that external filter, is mainly just a screen, and does not have any filter type paper in there.

 

If you want to add a cooler, I'd suggest routing the lines from the transmission, to the external cooler, and then into the radiator cooler, and back to the transmission. This will keep the trans fluid temp moderated in cold climates, and should eliminate the need for a thermostat to be installed.

[coldfusion21]

You can buy the whole external filter kit for like $20, which includes the filter. Yes, I know it's cheaper than buying just the filter. Go figure. That's what I did when I replaced the filter, just bought a whole kit.

 

BTW, that external filter, is mainly just a screen, and does not have any filter type paper in there.

 

If you want to add a cooler, I'd suggest routing the lines from the transmission, to the external cooler, and then into the radiator cooler, and back to the transmission. This will keep the trans fluid temp moderated in cold climates, and should eliminate the need for a thermostat to be installed.

 

Thanks! Lots of good info there. Not to sound rude, but how do you know that about the filter? have you seen the inside? I might just cut one up, for scientific purposes.

 

 

Do the universal transmission filter setups just use a engine oil filter? I want something fine enough to catch a lot of the junk but i'm worried a engine oil filter will clog to soon, or require short change intervals.

 

 

Edit:

http://www.wixfilters.com/filterlookup/PartDetail.asp?Part=51365

 

That is the Wix filter listing for the spin on filter on the tranny. Its just a generic oil filter. Looks to be the same as the 2.5 oil filter. Very interesting...

Edited December 28, 2009 by coldfusion21

[Legacy777]

I have not cut one open, but when I was looking at replacing mine, I received that information from one the local Subaru dealerships and another subaru shop I was talking with.

 

The purpose of the add on filter kit was to catch debris or what not from manufacturering.

 

By all means, if you want to cut one open, I'd be curious as well to see what's inside.

[OB99W]

I believe that the OEM part number for the filter kit is 31099AA091. Typically it sells for under $10, although shipping charges might also be about that amount.

[coldfusion21]

Well according to wix the 2.5 filter is the 4EAT filter as well (late model ones with the spin on)

 

I would be interested to know if the tranny filter # is the same as the oil filter # from subaru. If someone has that information.

 

I will probably gather parts this week and swap it all over next week. All that is needed is a remote oil filter mount and some fittings and hose. Cost should be under 50, maybe under 40 if the remote mount is cheap.

[bulwnkl]

Definitely not, unless they've changed quite recently. It makes sense (to me) that Wix would specify the same p/n for engine and tranny, just as Amsoil does. There's a tie-in there. However, from Subie, they're not the same part number nor are they the same filter. Personally, I wouldn't use anyone's engine oil filter there unless maybe it was Amsoil's EaO. Otherwise, I'd just buy the Subie spin-on. It's a bit expensive, but honestly it'll never need replaced again, or you can do it in 5 years if you really want to.