My 04 WRX wagon has been neglected due to my kids getting all the attention.
I've owned the car since new and rarely drive it hard. It has ~58K miles, and I'm getting ready to do a bunch of maintenance items. (Plugs, fuel filter, trans/diff oil).
In doing researching, I've decided on using the Subaru Extra S. My understanding is I won't need more than 4 quarts (or liters) if doing the transmission drain/refill. Is this correct? Best price I've been able to find is a 4 quart package from 42 Autosports. I'm a bit confused on what should go in the rear diff. From what I can gather, the Extra S isn't required, and is probably overkill. If so, what's a good, inexpensive alternative?
Lastly, since Extra S is synthetic, are there any concerns with putting that stuff in my transmission, which hasn't seen any new fluid for its entire life?
Any tips for a newbie doing this for the first time will also be greatly appreciated!
Thanks in advance.