So, I tried posting this on the Facebook page, but it quickly got lost in the YOHB shuffle. So, I went to the dealership to get Trans/Diff oil and was given a white bottle of 75W-90. I only got three bottles to do the front and rear diff. Forgetting that front diff and trans are basically the same, I went back to the same dealership to get more oil. I was then given black bottles of 80w-90 and told THAT is the stuff for STi's (I have an 09 STi). I have been unable to get any confirmation as to which one is actually correct and find it interesting that two trips to the same dealership yielded two different results. Any confirmation on which one should be used is greatly appreciated so that I can get this oil changed. Thank you in advance.
as long as it's Extra-S you'll be fine. the 80W90 may quiet down the trans noise but won't hurt anything other than add a little parasitic drag that would only concern a neurotic engineer/owner. I don't think the newer models require the friction modifier that older models needed and it won't hurt the diffs in your model.
That was another quandary. I can't see anywhere on the bottle where it says "extra-s". When I Google search extra-s, the bottles look the same as what i have. Also, can anyone send a shot of where the fill hole is?
trans is on passenger side between downpipe and trans, pull the dipstick to fill. rear diff will be a T-70? torx or 1/2" drive. rear diff will require a hose and gently squish the bottle till fluid starts to run. Make sure to do it level on stands or find a little bastard to do it for you... and it fill at the highest plug (may have a temp gauge instead)
Torx for front, not for rear. No dipstick in 09. I've done the rear before, just not sure about the front.
The difference in weight won't be major, I'd say you're fine to run either. I ran a cocktail in my trans and then 75w90 when I had my stock diff. Sent from my iPhone using Tapatalk