Trans and Diff gear oil Suggestions.

[waynlewis]

Hi.

I'm looking for a suitable/good transmission and gear oil for my 07 Subaru Impreza STI, to replace the OEM Extra-S. I've used Extra-S for my last 2 fluid changes, but now it's no longer available at the dealer and what they have now is only sold as a package deal w/service($200+). The transmission is a 6speed manual and per the manual uses GL-5 rated fluids, same for the center and rear diffs. Choices from the local stores are.. Valvoline, Mobil 1(which I've read wasn't to kind to our cars), SuperTech and Castrol. Those brands come in dino, syn-blend and full syn. Thanks.

 

[LoneRanger]

In the transmission you'll want one with no limited slip friction modifiers. The rear diff it doesn't matter and may even need the LS friction mods since it may have a mechanical LSD for the rear. I can't remember.

Or you could just order more Extra-S online from Fred Bean (that's actually what I would do):

http://www.fredbeansparts.com/subaru-75w90-extra-s-gear-and-transmission-quart-bottle.html

 

[guyonearth]

How often are you changing this?

 

[waynlewis]

Thanks for the link LoneRanger. I would do that also, but I'm heading up north to NC next weekend and wanted to get this changed out before then, that's why I was checking locally. But, if I can get it in time, I may go that route.

Guyonearth,
This is my 3rd time changing these fluids. The car has 147kmiles and I've owned it since 21kmiles, changed at 60, 100 and now.

 

[Padawan]

I chose to use the "Subaru Certified High-Performance Gear Oil" which is available online or from any Subaru dealer / parts department.

Part number for the quart container is SOA427V1700.

It seems to work very well in our '06 9-2x Aero in both the transmission and rear differential.

 

[901Memphis]

Redline would have my money if I ever needed a gear oil.

 

[sicko]

Can't help you on the transmission b/c my Subaru is an automatic that uses Subaru ATF-HP. But I've had Valvoline 75w-90 in my rear differential for about a year now and I've had no issues with it. Everything is smooth and quiet from the car's back end.

Check some WRX/STI forums, I'm sure there will be a ton of information regarding what fluid people have used in their transmissions.

 

[waynlewis]

I decided to go with SuperTech 75w90 syn-blend. It's API GL-5 approved (as states in the owners manual), will work in both trans and diffs, readily available and has gotten good reviews on LGT and a few WRX. I couldn't find Valvoline w/o LSD and everything else had LSD additive. If it doesn't work out, I'll just replace with Extra S when I get back or while I'm up there. Or I'll just change to Extra S anyway when I get back and use SuperTech as a clean change.

 

[waynlewis]

I'm driving up north to NC from South FL and want to get the change done before going.