I found out on another thread that the OEM Subaru transmission filter looks different than the engine oil filter. When doing a drain and fill on my Dad's 2002 automatic WRX I bought the filter from NAPA. NAPA specs the same spin-on NAPA Gold (1365) filter for the transmission and engine oil. The transmission has been working great the past few thousand miles since the d&f/filter change. Should I be concerned/switch out the filter for an OEM one? Could I switch out the filter without draining much fluid? If I remember correctly the filter looked to be high enough that it shouldn't drain much fluid. I plan on changing it again in 30,000 miles, so this won't be a particularly long change interval.