The Auto transmission on 2008 and earlier subarus use a filter. The filter bypasses must of the oil and only filters a small portion. The aftermarket ones filter 100%. There are reports that some folks using the aftermarket ones have had problems. If you go this route..purchase a Genuine Subaru filter.
Honestly though If you do a drain and fill every 10K miles you will probably be better off.
Honestly though If you do a drain and fill every 10K miles you will probably be better off.
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