70W-80 GL-5 MTF for Subarus

[twX]

My Subaru WRX requires 70W-80 gear oil for the manual transmission. It needs to be GL-5 since it shares fluid with the front diff. 75W-90 is also acceptable, but it can apparently make shifting really sluggish in cold weather, and I need something good for -40°C.

The Subaru Extra MT is only sold in 5-gallon pails and it's not cheap, so I'm looking for something else. It seems there are only two other options:

Motul Motylgear 75W-80 is a semi-synthetic GL-4/GL-5 MTF. I've heard mixed opinions about whether dual rated GL-4/GL-5 gear oils are as good as dedicated GL-5 for a transmission. I'm also not sold on its cold weather performance. The pour point is only -36°C, and there's no MRV published.

Fuchs Titan Sintofluid 75W-80 is a full synthetic GL-5 MTF designed for lifetime fill applications for euro cars like VW and BMW. It's got a much better pour point at -48°C, and MRV is low at 37,000 cP at -40°C. It seems to contain good amount of PAO.

Has anybody used either of these in a Subaru or other vehicle? Any opinions on GL-4/GL-5 vs GL-5? I'm leaning towards the Fuchs, since it's full synthetic and is almost the same price.

Motylgear data sheet
Fuchs data sheet

 

[Rand]

Thats quite odd the motul 75w85 is -46f.

definitely would skip the 75w80 with a PP of -32f in some parts of Canada.

The Flagship 75w90 Gear 300 is -65f (-54c)

I used the gear 300 and it was pretty sluggish when cold but you could get it into gear.
If I was buying any motul it would be the gear 300 75w90. Which was my favorite of the gear oils I tried in various MT equipped subarus.
2013 outback, 2011+2015 foresters.

Its pour point puts the redline 75w90ns to shame as well.

 

[slacktide_bitog]

PSC has a good price on a case of 12 Fuchs

 

[Rand]

PSC has a good price on a case of 12 Fuchs

135 shipped with tax not bad

 

[Overfill]

"GL-4/GL-5" is a GL-5, and it's just as good. If you just use the 75w as the critical cold weather determinant, then I would pick 75w80, as it will shift easiest cold. All of these MTFs should shift better than generic hypoid gear oil when hot, but the thinner ones (80) ought shift best. I wouldn't, however, run a thinner fluid than called out by Subaru.

My recommendation is the Motylgear 75w80

 

[Rand]

"GL-4/GL-5" is a GL-5, and it's just as good. If you just use the 75w as the critical cold weather determinant, then I would pick 75w80, as it will shift easiest cold. All of these MTFs should shift better than generic hypoid gear oil when hot, but the thinner ones (80) ought shift best. I wouldn't, however, run a thinner fluid than called out by Subaru.

My recommendation is the Motylgear 75w80

Did you miss that the gear oil you recommended has a PP of -32F?

While it might shift the best at 0f it could also be jello at -30f.

Its also quite odd that their similarly branded 75w85 has a pp of -46f

If the lowest temp I would see ever was around 0f the 75w80 would likely be the best shifting at that temp..
but Canada can be pretty cold. You dont want jello in the gearbox.

I would have to say the fuchs 75w80 seems far superior at least from a viscosity/extreme cold standpoint.

I had the 75w90 gear 300(-65f pp) out a few times around -10f it was ok. you just took your time. The car has to warm up a couple mins at that temp anyway IMO.
Nothing is going to shift like its 60f when its -10f out.

 

[Overfill]

Did you miss that the gear oil you recommended has a PP of -32F?

No, and that's why I phrased it the way I did.

Nothing is going to shift like its 60f when its -10f out.

If only.

Is all we've got pour point? Cause we're making this hinged a lot on pour point..

SAE-J306 specs that each grade has a dynamic viscosity of 150,000 mPa*s (aka cP) at the following maximum temps:

70W: -55C
75W: -40C
80W: -26C
85W: -12C

So it won't be jello. Pour point does not guarantee viscosities, and the testing has sufficient variance that i wouldn't stake my buy on it.

I don't know the whole market of gear oils, so if there's a 70w80 MTF that meets GL-5, one could go for that.

I understand it's tough on how to pick a better performer if one doesn't have a 70w option, but then again, how is any of this going to matter when it's going to be lousy (but fitting for the winter rating) at cold temps anyway.

 

[Rand]

I understand it's tough on how to pick a better performer if one doesn't have a 70w option, but then again, how is any of this going to matter when it's going to be lousy (but fitting for the winter rating) at cold temps anyway.

The fuchs mentioned above is 75w80 and has -48c Pour point. Any reason why would you recommend the motul over that?

 

[SubieRubyRoo]

Motul Gear 300 is what I always used, but HPL 75w90 wasn’t available at the time. These days, I’d use HPL Cold Climate 75w90, but @Pablo also had an Amsoil recommendation that could also be used in another thread like this but I can’t remember which product he recommended.

If you live in a cold climate, you definitely want something with good Brookfield results because even Gear 300 was difficult to get into 1st gear the first two-three shifts when it was below zero. The PAO in HPL CC would help with that. If you live in warmer climates, any of these is more than sufficient.

 

[Pablo]

You could try the MTG - Lower PP

https://www.amsoil.com/p/amsoil-75w-90-manual-transmission-transaxle-gear-lube-mtg/?zo=515729

https://www.amsoil.com/c/manual-transmission-fluid/21/?zo=515729

The thing is with these MT's, you go lower viscosity for winter, fine, no problem - but on hot days, the MT will get notchy into 2nd and 3rd

 

[twX]

I emailed Motul a while back requesting the MRV of the Motylgear 75W-80, but they haven't gotten back to me. I can't imagine it's very good given its poor pour point.

I don't think my transmission ever gets hot enough to warrant something thicker at operating temperature like a 75W-90.

I've decided to go with the Fuchs 75W-80. Eurodna.ca seems to be the best source for it in Canada. $95 CDN shipped for 4 L.

 

[ceecbtg]

Fuchs is a good decision.

 

[MolaKule]

Now that the OP has made his decision we see no need to further the discussion.