Subaru impreza gear oil question

[Planb]

Car is a 2004 impreza with the 4eat automatic transmission.

Manual recommends 80w90 for the front diff and 75w90 for the rear.

I just usually run 75w90 front and rear... But its time for a fluid change.

I have in stock 80w90 gl4/gl5 (how does this meet two different specifications?)

I also have in my stock some 75w140 should I run this gear lube?

 

[gathermewool]

I believe the EP additives not being as corrosive to yellow metals, such as with synchros, is what allows for a dual rating.

We kind of service will your Subie see?

What do you mean by, "in Stock"? Is this where you work or in your personal stash? Unless you already have the gear oil in your personal stash, I would stick with any brand-name GL-5 75W-90.

Unless you have some heavy duty plans for the Subie, the open from and rear differential probably won't benefit from an exotic or boutique oil, and I don't see any benefit in going heavier.

 

[Planb]

Do you think the word "stash" makes it sound like some sort of addiction?

I would pour in 75w90 gl5 normally but I just don't feel like buying any unless I was convinced otherwise...

Also, do you think a boutique gl5 gear oil is "better" over a name brand?

 

[dlundblad]

Originally Posted By: Planb
Also, do you think a boutique gl5 gear oil is "better" over a name brand?


Nope. The GL5 spec on the bottle is all you need.

 

[gathermewool]

Originally Posted By: Planb
Do you think the word "stash" makes it sound like some sort of addiction?

I would pour in 75w90 gl5 normally but I just don't feel like buying any unless I was convinced otherwise...

Also, do you think a boutique gl5 gear oil is "better" over a name brand?


I'm not sure if you were replying in jest or legitimately offended by my post, but "stash" is an accepted term for a collection of oil that one has that is in excess of current or near-future needs (ie, any more oil than is needed to cover the next vehicle's oil change in your garage, or even all upcoming oil changes for cars you maintain.)

Many find a sale or clearance on an known good oil and will buy out what's on the shelf. Some of these same people are known to then ask for what's in the back. Finally, these same people MAY just find another deal well before their current stash is depleted and buy that to add to their stash, too! It's not... Abnormal here.

I have a stash of German Castrol that's down to maybe 16 quarts, IIRC (another symptom of having a stash, is not remembering all of the oil that's in it...)

A boutique oil WILL be better than the cheapest GL-5 lube, but will it matter in most passengers cars? Probably not.

I ran Motul Gear 300 in my previous car, an 08 STI (limited slip front and rear). That stuff was something like $20/L. The Mobil 1 I replaced it with seemed to provide the same level of performance, for which me, a human being, is a very poor gage of.

If i had to bet, I'd say the Motul did protect better and would provide more at-limit and long-term protection.

For my XT, I haven't decided. I may do one change with a cheap synthetic, and then one final with a boutique oil and never touch it again. We'll see.