The gearbox, front diff, centre diff, and transfer case share lubrication (I'm generalizing and leaving out details but the point is, you only fill the gearbox to cover everything up front in your case).

The rear diff can use the same gear oil as the gearbox generally.

You can read this thread for info:
http://www.clubwrx.net/forums/gener...forums/general-maintenance-troubleshooting-accidents/showthread.php?t=134288720

or you can -- and should -- read your manual to select the correct viscosity for a GL5 (and I suspect MT-1) gear oil; in my area, it's 75W-90.

Then you can either pick something from the thread above, go buy regular Valvoline, or look into Subaru Extra-S. Your call.

 

How do ou actuly change it? Is it just like changing the engine oil. My friend says I will need to buy new seals.

 

Search "how to change transmission oil" and threads like this come up:
http://www.clubwrx.net/forums/powertrain/174035-diy-transmission-fluid-change.html

You will need to determine whether you have the conventional drain bolt on the gearbox or the torx unit instead. I don't know for your model.

You can buy a replacement crush washer for the gearbox and use RTV on the drain bolt on the rear diff. I use a torque wrench.

You do not need to remove the intercooler.

Does your friend own an Impreza?

 

What exactly do you mean when you ask what kind of oil should you use? The manual carries specific weights.

If you want to upgrade the oils, you can't go wrong with Royal Purple. There's other brands of the same caliber but they're the big name.

 

Just to throw in my $.02 here, Royal Purple was by far the WORST oil I've ever had in my transmissions. My 02 WRX was switched out to Royal Purple and it had all kinds of issues after that. Switched to a full redline and all of those problems disappeared. I've run Subaru fluid (best for brand new transmissions and worn transmission), Amsoil (best so far for general driving), Uncle Scotties CT (amazing combination, really hates the cold though), full Redline (does the job, but wouldn't say well), and Royal Purple. The RP was just horrible.

I know many people recommend their oils in other transmission and they very well may do well in those, but Subarus just don't seem to like it much.

 

From the avatars I think you guys have different gearboxes though. The 6spd may be OK with RP for all I know. What I am certain about though WRT RP is that I am... uncertain whether they actually make a GL5!

I looked on their site, and they say they have fluids that "exceed" GL4 or GL5 specs. This to me means they do not make a GL5

Anyone know, just for the benefit of people searching in the future (I don't use the stuff anyway)?

 

I don't see any specific GL-5 rated fluids, but their Max Gear fluid is supposed to be speifically for transmission and diffs that require GL-4 or GL-5 fluid, according to their site.

 

Yeah with the nature of what they do, sometimes they just list things as "exceeding" a certain very high rating. That doesn't mean a transmission will like it.

 

ok I will probably just get whatever oem is.