Redline Oil Gurus: Subaru gear oil question

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Is there any harm in putting a gear oil designed for limited slip differentials in a non limited slip differential? My Subaru Crosstrek manual calls for a 75W-90 GL-5 oil to be used in the rear diff. It is not LSD. I was planning on using Redline 75W-90NS in the front diff/transmission. It is a 6 spd manual and they share a common sump. Would there be any harm if I use the Redline 75W-90NS in the rear diff also or would I have better protection using the regular Redline 75W-90 gear oil in the rear diff?
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Joined
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Messages
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After doing more research, I think I'll go with the Motul Gear 300 75W-90. Seems like it does well in the Subaru manual transmissions and rear diffs.👍
Cant seem to get multiquote to work

Motul is a good choice I ran it in 3 subarus. The redline is ok too.

Stay away from forum based blends and mixes.. I know for awhile they were mixing the shockproof with whatever and calling it some kind of blend.

IIRC extra MT is a thinner gl-5 gear oil. So it may shift different when its extra cold out..
I had no issues except the skyrocketing price with motul gear 300.
2011 Forester, 2015 forester, 2013 outback (all MT)
 
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Why dont just follow redline recommendation ? MTL for manual trans and standard 75W-90 at rear differential ? Are we more knowledgeable than the oil producer ?
 
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is that ok for manual transmission usage?
Yes it is, MT needs GL5 75w90. Nice shifting too.

Edit: It is also sold as a manual transmission fluid. This is good for the Subaru with shared sump front diff.

 
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Yes it is, MT needs GL5 75w90. Nice shifting too.

Edit: It is also sold as a manual transmission fluid. This is good for the Subaru with shared sump front diff.

Thanks for the update.
That second link is much better the amazon link was anemic on details
 
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Why dont just follow redline recommendation ? MTL for manual trans and standard 75W-90 at rear differential ? Are we more knowledgeable than the oil producer ?
Redline MTL is not compatible with subaru MT.
you need 75w90NS for a redline product.
Subaru has combined sump design that shares front diff with MT.. This requires GL-5 for the hypoid gears.

I have emailed redline to see if their product recommender is wrong.
 
Last edited:

dezlpwr

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Feb 22, 2009
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Why dont just follow redline recommendation ? MTL for manual trans and standard 75W-90 at rear differential ? Are we more knowledgeable than the oil producer ?
Subaru changed their oil recommendation to 75W-50 GL-5 in both the manual transmission/front diff and rear diff. It appears as though Redline has not updated this change in their application recommendations on their website. That's why I was asking my question about what to use now.
 

dezlpwr

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Messages
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Location
Gig Harbor, WA
Redline MTL is not compatible with subaru MT.
you need 75w90NS for a redline product.
Subaru has combined sump design that shares front diff with MT.. This requires GL-5 for the hypoid gears.

I have emailed redline to see if their product recommender is wrong.
I emailed them also. No reply. I do believe the recommendation is outdated since Subaru changed to a 75W-90 GL-5 recommendation in everything. I was going to use Motul 300 75w-90 but I can't find it anywhere. I agree with you, the Redline 75w-90NS will work in everything.👍
 
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I emailed them also. No reply. I do believe the recommendation is outdated since Subaru changed to a 75W-90 GL-5 recommendation in everything. I was going to use Motul 300 75w-90 but I can't find it anywhere. I agree with you, the Redline 75w-90NS will work in everything.👍

Outdated might be the wrong word. Subaru has speced only gl-5 for as long as I can remember in any of their shared MT+Diff applications.
 
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I emailed them also. No reply. I do believe the recommendation is outdated since Subaru changed to a 75W-90 GL-5 recommendation in everything. I was going to use Motul 300 75w-90 but I can't find it anywhere. I agree with you, the Redline 75w-90NS will work in everything.👍
They don’t respond on weekends, I’m sure
 
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Outdated might be the wrong word. Subaru has speced only gl-5 for as long as I can remember in any of their shared MT+Diff applications.
On this part, I dont really trust Subaru recommendation, they backtrack the spec going back to 75w-90 after their Extra MT cause excessive wear and noise for the rear differential.
 
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On this part, I dont really trust Subaru recommendation, they backtrack the spec going back to 75w-90 after their Extra MT cause excessive wear and noise for the rear differential.
What years did they recommend extra MT for the rear diff.
I was more into it in the 2005-2017 subaru era.
back then the fanciest thing was subaru Extra-S.

I got some from dealer and it shifted like crap.. went back to redline. then motul.
 
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