Mobile 1 in a Subaru Manual transaxle?

Originally Posted by someoldguy
I know he is a GM Certified Master Mechanic.. and has rebuilt thousands of transmissions...


Due to his recommending engine oil in a highly stressed transmissions ....
 
Originally Posted by someoldguy
..... The Question: does anyone know if this can be done with a Subaru manual transaxle?

Thanks


Nope.
Subaru (expect for the Justy) use longitudinally mounted engine and trans.
Therefore you have to divert torque 90 degrees.
This is a high stress and high loss point

it requires a special GL-5, 4 hypoid gear lube.

It is unfortunately shared with the MT.

Extra-S was the go to. IDK if its even available anymore.

I think there have been many threads on what worked well as a substitute.
My wife is A/T now with a longlife fill so - I don't have this concern.
_____________________

I wonder what SoA are using in Indiana?

Maybe give the sales guy at Idemitsu Indiana a ring up.
They have been very responsive to me in the past.
Also below the Dev Lab number, but I would go sales first.


Idemitsu Research &
Development Center
48325 Alpha Drive, Suite 200
Wixom, MI 48393
(248) 675-4345


Headquarters & Manufacturing Facility
Idemitsu Lubricants America Corporation
701 Port Road
Jeffersonville, IN 47130-8425
www.ILAcorp.com
 
The new Subaru stuff is from Idemitsu as well, supposedly similar to Extra-S. The two Subies I care for use M1 75W-90 but they are automatics.
 
Originally Posted by LoneRanger
The center differential in manual transmission Subaru is a viscous type, is a sealed unit, and does not share the gear oil that's shared between the manual transmission and the front differential. Confused yet? It's Subaru, they're weird. Cool as heck and great vehicles, but a little different from the norm !!


The thing I've seen not only through my own 10+ years of Subaru ownership and reading several Subaru boards, is that yes, Subaru is affectionately "weird" when viewed through the eyes of American vehicle requirements. However, (pre-CVT exclusion here) when the owner uses ONLY fluids that meet Subaru specs for engine, diffs, & trans, they will generally last the life of the vehicle. When people think they're getting all crafty and "better" (see Uncle Scotty's cocktail (USC), etc...) the results go downhill quickly. You would see about half the people that had apparent good results with USC, and half that hated it immediately like I did, and then a 6-month followup at least half that thought it had been good had drained it because it went to crud as well.

The requirements may be different than other manufacturers, but correct fluids are not hard to find. If you're going to play roulette with a big ticket item like the trans, how about just leaving it as is and shipping the vehicle to me with a signed title in the glovebox? I promise to give it good care and feeding!
 
From what I have read, Extra-S may still be available in Canada, but is no longer in the USA. The High Performance Gear meets the specs, but isnt quite the same. Rumors on the various Subaru forums are that the dealerships put in Valvoline GL-5 gear oil when brought in for service.

I may try some Motul Gear or MotylGear (semi syn) for my next change, but would love to get Extra-S if I ever have to travel across the border....
 
Originally Posted by someoldguy
Well Bob: I have an odd question: I was told by the master mechanic that rebuilds trannies to use Mobil 1 0-50 synthetic motor oil in my Dodge Cummins NV4500 instead of gear lube: was told it runs cooler and lubes better. So I did it.. and the transmission ran quieter and has been problem free for about 25,000 miles. The Question: does anyone know if this can be done with a Subaru manual transaxle?

Thanks


One thing you need to realize is that Hypoid differentials require a lubricant that has an EP additive which gives them a GL-5 protection and wear rating. Engine oils do not.

Most manual transmissions require a GL-4 rated lubricant in which the formulation has to have specific friction modifiers. Engine oils do not have this.

In other than Subaru's manual transaxles (combo manual transmission and differential) the differential is a spider gear system that only requires a GL-4 rated lubricant.

The manual Subaru's have a driveline system in which the transmission sump shares lubricant with the differential. This means it has to have s special lubricant lubricant to protect the differential AND the proper friction modification for the transmission. Engine oils cannot serve these two functions.

The mechanic may be a good gearhead but he lacks understanding of lubricant formulations and the proper role of each type of lubricant.
 
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Can't you guys tell a trollpost when you see one?
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I'm nearly six months late to this thread. I'm about to change the fluid in my 2017 manual transmission Crosstrek with 50K miles. The owner's manual simply says SUBARU Extra MT, with GL-5 75W90 being an alternative, although the footnote says that the latter will reduce fuel economy and driving efficiency. It makes no mention of the gear oil having the presence or absence of friction modifiers. To that end, I had already bought Supertech 75W90 synthetic gear oil before seeing this thread.

A quick search for the Subaru gear oil shows a price of $415 for five gallons, basically $20/quart plus shipping. I believe I'll just use the SuperTech.
 
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