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If i wanted to change my transmission fluid to synthetic would i have to drain it from all three differentials?
 

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Not a single reason to make them all the same. They are all separate from each other.

Keep in mind that the differentials are very particular about what type of fluids you use in them.
 

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SBC-ID - in auto mode do the gain settings mean anything ???

I've noticed that now that it's getting colder out my stick is feeling a little "notchy". It seems that up until it's been driven for 10-15mins. it's a little more difficult to get it into gear. I've got almost 6k miles on her and would like to switch over to a synthetic transmission fluid (thinking Motul). Curious if anyone's made the change yet or had any words of advice......
 

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I am also curious what people have used.

I am at about 9k and would like to change the trans and diff fuilds around 10k but am not sure yet what brand to use. I really like the Amsoil motor oil I use but hear their trans fluid lubricates too well, at least their Series 2000 does, so I am not sure. I am leaning towards still using Amsoil but just their regular synthetic gear oil.
 

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White/Gold in Michigan

Well.....I just spoke w/my dealership and their service manager said transmission/differential fluids aren't due for a change till the 30k mark. I am still leaning towards an early switch to synthetic though, as the "stiffness" in the first 10-15mins. is somewhat unnerving. I am looking into Motul but need to do some more preliminary research first. Has anyone switched out these fluids already that can possibly offer some insight?
 

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I have not changed the fluids on my STi yet. I just want to offer my opinion. You are correct. The Synthetic based lubricants will offer a better "feel" to your stick when your car is cold. They provide a quicker rise in temperature and pressure. I would not recomend a change in fliud weight. I think the change from a conventional to synthetic is exactly what you might be looking for. It is very noticeable in transmissions/differentials. Motul is an excellent product. I used it before on my GTI, when I was living in Europe. I am no expert on this subject. It's just my experience; I do work on airplanes for a living.
I use Amsoil now, it's very easy for me to order online. They provide an excellent product line of lubricants as well.
You can also consider Royal Purple, Redline, Amsoil. I feel those are the best for your money. I don't think you can go wrong with any of them. It's really a matter of convenience.
MKIVSupra I'm not really sure what you mean by lubricating to well. I have read that some fluids don't build enough pressure, therefore not providing realiable shifts or even losing power at the wheels.
 

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Well I heard that the Amsoil Series 2000 gear oil has real good lubrication properties which is good for the bearings and will give you better gas mileage. Only problem is when it comes to the synchros, they like some friction. If you are a hard/quick shifter you can have problems down the road with some synthetic lubricants that could make it harder to shift into gear. Like I said, since I was so happy with the Amsoil motor oil and their products are easy for me to get I would like to try their gear oil. I was thinking of going with the series 2000 stuff in the rear diff and using their regular gear oil in the trans.
 

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UPDATE

It makes sense. I am going to try and contact Amsoil and ask them for a recomendation or advice. So many people here with questions about synthetic and conventional oil for their engines. Some even get into right out flaming over it. The gear oils are probably completely over looked. A crucial part of the whole picture when it comes to performance and sustained life. If everyone just followed the correct maintenace intervals, they would not have any problems. Oil analysis is the way to go.

By the way... One more question? Did you use the Amsoil oil filter. I have (wife's) Forester and it appears to use the same oil filter.
PN# SDF20
Would you happen to know if that is correct?
 

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Yes that is the one I used and was recommended by my Amsoil guy. He double checked and that was what Amsoil said to use. So far almost 3k miles and no problems.

BTW, if you go with Amsoil oil and filter don't forget Subaru crush washers for you drain plug.
 

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Thanks! I'm just full of questions. Where did you get the crush washers? I'm assuming the subary dealership. Sometimes I can get away with using aircraft hardware. Thanks again. Obviously I'm new to the forum. This place is very cool. Lots of good people.
 

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K&N vs Green Filter

You can get them at any Subaru dealership. I got mine from www.subaruparts.com along with some touchup paint and a trunk net. I ordered 5 of them since they are only around $.65 a piece I think.
 
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