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2007 Forester 2.5X AT
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27 Posts
Discussion Starter · #1 ·
Today I drained and filled my 4eat with 3.75 qts of Redline D4 atf. This is for an '07 with 142,000 miles. I had been doing drain and fills with the type HP fluid until now (every 10-15K). The reason I went with the synthetic is that the transmission performs poorly before the vehicle fully warms up (with the HP fluid). It shifts very hard (particularly from 3 to 4) when cold, and has always done this. I wanted to see if the better cold flow properties of a synthetic fluid would improve the performance. The Redline seemed to have the best cold flow properties of any of the fluids that claim to be a substitute for type HP. I wanted to report the results of this, as I know many others are curious about using an aftermarket fluid in a type HP application as well.

So far, nothing bad has happened. It seems to shift at least as well as before. The true test will be leaving it out overnight and seeing if the hard shifting goes away. I'll probably report back on that in a week or so. If I see any improvement, I will probably start using this fluid.

I realize that I only have about 40% synthetic and 60% type HP, but I was hoping that there would be some improvement. I guess we'll see.
 

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2007 Forester 2.5X AT
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27 Posts
Discussion Starter · #3 ·
Update

I let the Forester sit overnight in the cold. I took it out for a test drive and it stills shifts hard when cold. In fact, it may be a little worse as it now clunks a little bit shifting from 1 to 2. When it warms up, it still does fine.

As of now, it looks like this experiment has not really helped or hurt. I may be going back to the HP fluid for my next change.
 

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Administrator
2007 Forester Sports XT 4EAT
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40,552 Posts
Have you replaced the ATF filter along with your drain & refill routine? If not, that's something to try? :confused:

Both our Foresters were switch to Red Line synthetic ATF when the mileage was under 30K miles. It included a system flush to remove all traces of the old ATF, but oddly, the Subaru dealership shop didn't replace the ATF filter... said it considered a non-maintenance item? Next time I'm going to request the ATF filter be changed. :wink:

Bobby...

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

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2007 Forester 2.5X AT
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27 Posts
Discussion Starter · #5 ·
I have tried changing the filter before, with no change in performance.

The 40% redline doesn't seem to be having much of an impact at this point. Maybe a little better, but it's hard to tell. I may use it again my next drain and fill, just to see.
 

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2008 Forester X 4EAT
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I have tried changing the filter before, with no change in performance.

The 40% redline doesn't seem to be having much of an impact at this point. Maybe a little better, but it's hard to tell. I may use it again my next drain and fill, just to see.
I'm preparing to switch to Redline as well. Our '08 Forester with just a hair over 50k miles has exactly the same behavior, as did my '06 9-2x. I drained-refilled-repeated with Subaru OEM ATF on my 9-2x at 50k miles, as well as replaced the filter. There was only a very minor improvement in cold weather shifting. Having that experience to compare to, I'm hoping I will notice a large improvement with the almost twice as expensive synthetic Redline ATF I plan to use in the Forester.
 

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2008 Forester X 4EAT
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I ordered ten quarts of the Redline D4 and a replacement filter via Amazon Prime last night. ~$133.00 shipped for everything. I will do the drain/refill/repeat this Saturday, and hopefully have some positive results to report back within a week.
 

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2019 Crosstrek 2018 XT
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14,713 Posts
I seriously doubt you will see any improvement with the Redline. I have been using the HP for 118K miles now. My tranny runs like the day it was new. Overnight outside at 0F..no problems. As always/usual..I could be wrong. I think RedLine makes good products. Their engine oil is great.
 

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2007 Forester 2.5X AT
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27 Posts
Discussion Starter · #9 ·
It's been about a month since I put the Redline in, and the results are inconclusive at best. It still has the same cold shifting issues, but it seems like it may not be quite as bad. It kind of feels like it may not be taking as long to get back to "normal" shifting, but this could just be my imagination. Again, I've only got about 40% Redline in at this point, so I'm tempted to use it again for my next drain and fill to see if it improves.

Using the product doesn't seem to have created any problems, which is the most important thing.
 
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