Gl5 75w90 in WRX manual?

[wheelman]

The manual for my 2011 WRX doesn't specify much other than 75w90 gl5.
Mobil 1 and Valvoline both say their synthetic 75w90 with limited slip additive would work fine. That doesn't seem to make sense to me. I'd like to hear from a technical stand point how that is correct or if it isn't how it's not. I've been told to run boutique oils but would prefer to use something more widely available if possible. Is it really as simple as any 75w90 gl5 will work?

 

[Greasymechtech]

I would not use LS additive GL5

Use the Subaru gear oil or ANY non-LS GL5.... Like Redline NS, MPT NFM, Torco SGO, Motul Gear300, Idemitsu, or the Mack GO-J Plus list.

LS additives don't help with synchro function, do increase oxidation rate(fluid degradation), and can be harsh on gasket/seal materials.

So, I don't recommend LS gear oils in manual transmission. I don't have a problem with non-LS GL5's in manual transmissions. I could care less about the pre dosed LS gear oils and avoid them.

 

[SubieRubyRoo]

Search my thread on lab results of 75w90s. +1 on not using any gear oil with LS additive in Subaru.

You can always use HPL as it is safe in GL4 and GL5 applications.

 

[wheelman]

Search my thread on lab results of 75w90s. +1 on not using any gear oil with LS additive in Subaru.

You can always use HPL as it is safe in GL4 and GL5 applications.

What is hpl?

 

[SubieRubyRoo]

What is hpl?

@High Performance Lubricants

Purchase from advlubricants.com; use code BITOG15 for 15% off.

HPL is a BITOG sponsor, and produces some of the most robust oils available to the everyman. Yes, it’s more expensive. Yes, it lasts longer. Yes, if you want the best that money can buy, it’s HPL. No, it’s not for everyone. There’s a bunch of threads on HPL’s offerings.

 

[wheelman]

I would not use LS additive GL5

Use the Subaru gear oil or ANY non-LS GL5.... Like Redline NS, MPT NFM, Torco SGO, Motul Gear300, Idemitsu, or the Mack GO-J Plus list.

LS additives don't help with synchro function, do increase oxidation rate(fluid degradation), and can be harsh on gasket/seal materials.

So, I don't recommend LS gear oils in manual transmission. I don't have a problem with non-LS GL5's in manual transmissions. I could care less about the pre dosed LS gear oils and avoid them.

A non ls product in the part stores would be a regular dino 75w90 correct?

 

[slacktide_bitog]

For the transmission/front diff, use only Motul Gear 300.

For the rear diff, any 75w90 GL5 is fine

Also, the front diff on automatic Subarus can use any 75w90 GL5 with no problem.

 

[SubieRubyRoo]

Non-LS does not preclude synthetic gear oils. You’re co-mingling things that aren’t necessarily joined.

You can have:
conventional non-LS
Conventional LS
Synthetic non-LS
Synthetic LS

If you want a really good non-LS synthetic, Motul Gear 300 is proven in Subarus, but if your area gets well below zero Gear 300 is known to be pretty stiff shifting when cold in manual trannies. Gear 300 is fine in the differentials regardless of temps.

 

[Greasymechtech]

A non ls product in the part stores would be a regular dino 75w90 correct?

No... you'd have to read the label

 

[wheelman]

No... you'd have to read the label

No... you'd have to read the label

Non-LS does not preclude synthetic gear oils. You’re co-mingling things that aren’t necessarily joined.

You can have:
conventional non-LS
Conventional LS
Synthetic non-LS
Synthetic LS

If you want a really good non-LS synthetic, Motul Gear 300 is proven in Subarus, but if your area gets well below zero Gear 300 is known to be pretty stiff shifting when cold in manual trannies. Gear 300 is fine in the differentials regardless of temps.

I think you guys misunderstand what I'm saying.
I'm not saying that you can't get a synthetic gear oil that doesn't have limited slip additive. What I'm saying is that your general part stores AutoZone O'Reilly's etc don't generally have synthetic gear oils that do not contain limited slip additives so if I want to get a product that I can get in a store and is widely available and I don't have to order it over the internet I'm probably going to have to use a regular conventional gear oil that doesn't have limited slip additive because they don't typically have synthetics without limited slip additives.

 

[bullwinkle]

Does a Subaru have brass syncros in the transmission? If so, GL-5 might not be a good idea. Synthetic GL-4 always worked better for me (Toyotas, mostly).

 

[SubieRubyRoo]

Does a Subaru have brass syncros in the transmission? If so, GL-5 might not be a good idea. Synthetic GL-4 always worked better for me (Toyotas, mostly).

Hence, the HPL recommendation since they do not use sulfur as an EP additive, and it is perfectly safe in GL4 and GL5 applications. Motul Gear 300 also fits the same bill, and is actually fairly similar in most performance metrics.

However, HPL is:
1. Available (direct from mfr, no less!)
2. Cheaper per quart
3. MADE IN THE USA

 

[twX]

LS additives don't help with synchro function, do increase oxidation rate(fluid degradation), and can be harsh on gasket/seal materials.

So, I don't recommend LS gear oils in manual transmission.

+1 on not using any gear oil with LS additive in Subaru.

Is this a concern for the rear diff as well? I just picked up some Redline 75W85 GL-5 for the rear diff on my 2015 WRX, which contains some LS additive.

 

[SubLGT]

.....so if I want to get a product that I can get in a store and is widely available and I don't have to order it over the internet I'm probably going to have to use a regular conventional gear oil that doesn't have limited slip additive because they don't typically have synthetics without limited slip additives.

Ask your local parts store to order some Motul Gear 300 for you.

 

[wheelman]

Ask your local parts store to order some Motul Gear 300 for you.

They can't. Tried that route.

 

[SubLGT]

Buy the Subaru OE gear oil at you local Subaru dealer.

 

[wheelman]

Buy the Subaru OE gear oil at you local Subaru dealer.

Closest Subaru dealer is about 1 hour away and there customer service is lacking! Hence why I'd like to source a local option.

 

[SubLGT]

.... Is it really as simple as any 75w90 gl5 will work?

No, not in a Subaru manual transmission. Do some searching at forums.nasioc.com to find out what oil brands will work best in your 2011 WRX.

 

[wheelman]

No, not in a Subaru manual transmission. Do some searching at forums.nasioc.com to find out what oil brands will work best in your 2011 WRX.

Mr Subaru put 80w90 in his Subaru manual transmission. It was a part store brand gear oil to.

 

[SubLGT]

They can't. Tried that route.

Check with a local powersports dealer. Or use the find-a-dealer search at Motul's website.