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2015 Forester
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8 Posts
Discussion Starter · #1 ·
My wife and I are buying a 2007 Forester from close friends and giving it to our grandson.
It has automatic transmission, with 96,000 miles.
It's been perfectly, maybe even slightly obsessively, serviced all the time and has no problems of tranny or any kind.

I want it to last him a long time and many many miles, so so want to load the dice in his favor so think a full transmission flush/service is a prudent pre-emptive service. Yeah, I know, we don't HAVE to do tranny flushes.

One concern about doing that came up when I thought of paying him to take it in to a reputable tranny shop for a flush and routine service (drop the pan, replace the external canister filter, etc.) came up with the issue of the external canister filter. Apparently some tranny shops will use standard oil filters that are mechanically superficially compatible, but not internally designed like the OEM official Subaru tranny filters.
At least that the case made at this video:
youtube.com
Subaru automatic transmission filter vs oil filters. *
It was some issue about the bypass valve in the non-Subaru-branded filters not being set to the right pressure or something like that.

Although I don't hesitate to use non-Subaru brand oil filters for the routine engine oil changes, that video did make sense to me (yeah, the guy does talk painfully slowly and the video could be far shorter<sigh>).

So my questions to you Subie experts are:
Is that story (which is essentially "INSIST on using the OEM filter") correct?
Is my thought that spending $150 on a complete tranny flush/service is a good investment reasonable?
(In other words, I'm sort of caught between "an ounce of prevention is worth a pound of cure" and "if it ain't broke don't fix it.")

Any thoughts or knowledge?

Al
* Sorry, I couldn't post the actual youtube link because I'm a newbie here in this forum and don't have that right yet.

Additional question to my own post:
Any thoughts on using full synthetic transmission fluid if going to the trouble of a full flush exchange?
 

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Administrator
2007 Forester Sports XT 4EAT
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40,840 Posts
"if it ain't broke don't fix it."
@inquirer I tend to lean towards this. :wink:

Normally a transmission flush is not recommended, unless it been done early on. Most members would recommend an ATF drain & refill regiment.

ATF filter...
Subaru considers this a "non-service item", meaning it's only replaced if the transmission is repaired. That doesn't mean you can't replace it, if that's something you want to do. Be aware this is a special filter! Take a look at this post & this post in another thread.

ATF...
We have Redline full synthetic ATF in both our Foresters. NOT a recommendation, just we decided to use.

Engine oi & oil filter...
We use Valvoline SYNPower full synthetic, 5W-30 & WIX 57712 oil filters. Again, NOT a recommendation, just we use.

My wife and I are buying a 2007 Forester from close friends and giving it to our grandson.
Make sure you check for head gasket seepage or leaking, which could indicate the head gaskets are failing! This can = a VERY expensive repair! :icon_eek:

Bobby...

['07 FSXT MODding Journal] ['03 X MODding Journal]
 

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1999 A/T - 235,000 mi. WA state
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890 Posts
Nice gift. Low miles and maintained!

I'd do the flush. I had my tranny flushed early and the screw-on filter replaced, even though dealer was surprised / saying it was a lifetime filter. Have serviced fluid more often than spec'd; now at 230,000 the tranny is the most solid of the major components; now on its 3rd screw-on filter.

Filter choice. I've used Subaru filters at the dealer.

Independent shop vs. dealer; choose dealer. Along about 175,000 I let an independent shop flush the tranny, good price quote, after they assured me they had the correct fluid. Later the tranny overheat light came on at 20F in Montana. I went to my local Subie dealer for a tranny flush and warning light never came back on.
 

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2005 Forester Automatic
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495 Posts
The fluid filter for the 4EAT is not a really fine filter -- its there to catch large particles that occur when a transmission dies, basically to attempt to protect the rest of the transmission to make the rebuild easier. Changing it out, if the tranny is working fine, brings little or nothing. The ONE thing changing the filter does do, is gets a little more fluid out of the system.

Flushes versus serial drain and fills. Topic has been debated for years, and far beyond subies. Me, I am convinced that the pressure flush machines that the shops use often cause more trouble than they are worth. They can stir up pockets of crud, filings and sludge that would have better been left alone. Remember, there is NO proper filter in the system, not one intended for the 2 -20 micron size particles that we debate about in engine oil for sure, and probably not for stuff much larger than that. That stuff just settles out in automatic trannies. As the saying goes, leave a sleeping dog lay-- well leave a sleeping filing lay too.

The drain and fill process is gentle. You take the plug out, filter perhaps the first time and you get around 4.5 quarts out. Measure it carefully. Replace with same amount new. Get tranny hot and check level in park, on level surface. Should be around top notch.

You have now replaced around 45% of the old fluid. Do it again, this time w/o hassle and cost of filter, assume 4 Q out. You will drain about 2.2 quarts of "old fluid" and 1.8 quarts of "new fluid". Replace with 4q new. Now you are at 6.8q of new fluid and 3.2q of old (10q 4EAT capacity).

Some purists would suggest a third drain. 4 q out. 2.7q new fluid and 1.3q of old. 4 more Q new and you now have 8.1 quarts of new and 1.9 old. Its likely that even the flush systems don't do much better than this. Me, I decided to do the third flush after another 20k miles. The fluid that came out at 20k later (6.8 new and 3.2 old mix) looked fine.

I did these measures with a tranny that had had unknown maint. the old fluid looked brown and nasty. It did not take a full flush to make it look better. It always shifted fine, but now I have the knowledge that the additive package in place is new and robust.

I used amsoil. Was cheaper than Subaru ATF-HD
 
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