Subaru High Performance Gear Oil vs Subaru Extra S

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These VOA’s are courtesy of JarHams on nasioc and are posted in the Car Part Reviews forum there. The main reason for the voa’s is because Subaru of America sent a letter to dealers stating that the HPGO 75W-90 “is available as an alternative to the current K0322AA093 75W-90 Go Extra S Gear Oil that is supplied in a 5 Gallon Pail”, while inquiries to SoA by some customers (and even some dealers) claimed that it was the same product. Although the Extra S is made by Showa Shell Sekiyu and the HPGO is made by Idemitsu. Dealers have access to the MSDS, so maybe it will eventually show up soon on-line. Both samples dated 1 Nov 2014 Extra S (Similar to what we’ve already seen) Boron 361 Silicon 4 Calcium 1178 Magnesium 988 Phosphorous 1173 Properties cSt Viscosity @ 100C 13.34 Flashpoint: 400 TAN: 4.8 Comments: This is the sample of Extra S sample of 75W/90. The additives present are boron, calcium, magnesium, and phosphorus. The viscosity is correct for 75W/90 and there’s no moisture or insoluble present. The TAN is 4.8. This is serviceable oil. Subaru High Performance Gear Oil (hey, who took my metallic additives?) Boron 124 Silicon 6 Phosphorous 902 Properties Viscosity @ 100C 15.04 Flashpoint: 425 TAN: 3.4 Comments: This is the sample of the High Performance 75W/90. The additives are very different from the Extra S, so this is not the same oil. That’s not to say that one is better than the other or that this oil isn’t serviceable, but the two aren’t the same. No moisture or insolubles are present. The TAN is 3.4. Is there any chance that sulfur in the HPGO is higher than in the Extra S? popcorn -Dennis
 
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I've got the HPGO in my Forester now. It shifts like it did originally, for whatever that's worth. I tried Amsoil 75w-110, which was very poor, and a waste.
 
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Thanks Dennis. It appears the Subaru HPGO is using a more modern additive system. I have no idea if it's as good or not. What do Subaru racing teams use? Is Extra-S still preferred by the track guys? If so I'd go with that still.
 

bluesubie

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Originally Posted By: buster
What do Subaru racing teams use? Is Extra-S still preferred by the track guys? If so I'd go with that still.
When I toured Vermont Rally Car a year ago, they had plenty of Motul Gear 300 on hand. Now they're sponsored by RP and most people don't have many good things to say about their gear oil in a Subaru. Different gearbox in the rally cars though. And with the introduction of HPGO, I don't believe SoA/dealers will even be getting those pails of Extra S any longer. Lol, oaklandish. Thanks for pointing out this voa to me on nasioc! -Dennis
 
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What is OEM in 2014 WRX? It sure went to heck under 1500 miles! Every shift was a real grind. I drained and slightly overfilled with Amsoil SVT 75W-110 headed to 8k miles now and still great. All shifts are like butter now. Bill in Utah and others have been using the 110 for years now.
 

bluesubie

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Originally Posted By: Pablo
What is OEM in 2014 WRX? It sure went to heck under 1500 miles! Every shift was a real grind.
I've read all sorts of things, but since Idemitsu makes the factory fill engine oil and the new HPGO is also made by Idemitsu, my guess is that it is possibly now made by Idemitsu. It's probably better than the Mobil Conventional 80W-90 that my dealer uses. You need a sledge hammer to shift with that stuff when it's below freezing outside! -Dennis
 
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MolaKule

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The <span style="font-weight: bold">Extra S</span> appears to be a true 75W90 MTL, while the <span style="font-weight: bold">Subaru High Performance Gear Oil</span> appears to be a run-of-the-mill differential lube.
 
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