At 58,000 miles I'm ready to change the front and rear gear oil in my 2003 Forester XS (Auto). The book specifies 75W-90 for the rear diff, and 80W-90 in the front. I'd like to go synthetic with Mobil 1, but it's only available in 75W-90.
My question: Would it be OK to use the Mobil 1 75W-90 in the front diff ?? I'm thinking that it's so close it should be OK, but Subaru's recommending a different weight makes me wonder...
I'd appreciate any thoughts/advice on this.
TIA
I've been using it for 102,000 miles without an issue. ed
As others say, I don't think there would be an issue. I'm just writing to say a lot of people also like Redline's products. I'm sure there are several other brands that would be adequate.
I think you'll have a hard time finding a synthetic 80w-90 gear oil. The properties of synthetic lube give it a wider spread, "naturally" so to speak.
I've been using Mobil1 in both differentials of my Impreza with no problems and highly recommend it. By the way, Mobil (Exxon-Mobil, that is) is a great company. Yeah, they do rip us off on gasoline, all energy companies do nowadays, but Mobil has well tested quality products and a great customer service.
I remember once buying a sealed case of their synthetic oil, off the shelf at Walmart, only to find that it contains regular non-synthetic oil :-O After some investigation by Mobil I was refunded all my money, plus I got the case of regular oil for free, and I also got an apology from them. I thought the 20 or so dollars I spent were a goner.
MN
Thanks to all for your advice - I'm going to do it....
How can you tell? Did your inner child tell you to do the oil analysis?
No, the sealed case of presumed synthetic actually contained six blue bottles of regular dino Mobil oil. What kind of oil was in those? I have no idea, maybe synthetic but I doubt it.
Anyway, Mobil was very helpful in a difficult and suspicious situation. They conducted an investigation and refunded me my money with an apology- supposedly they had a mess-up at their facilities.
MN
Oh, I saw 5 qt. jugs which were about 2/3 the price of the boxed oil and thought you went for those. I guess I'll just go for the jugs and hope they poured the right stuff in.
I wonder if Cosco sells motor oil by the barrel...
The mixup happened in 1997. As I recall the 5qt jugs were not widely available then. I have learned from the experience to always check the contents of any larger case, and also to inspect the caps on jugs and individual bottles for signs of tampering. Synthetic is expensive.
MN
I now check every oil container to see if its been opened. I was about to buy 3 quarts of Mobil 1 gear oil and noticed that one of the little
1/4 inch long caps was a different color. I smelled all bottles and there was a big difference. I suspected some jerk used the Mobil and replaced it with motor oil or? I contacted Mobil and never heard anything again. This was at Advanced Auto.
I don't know if the Forester XS is so equipped, but if it has an LSD in the rear, that may require a different fluid. Something to do with friction modifiers (or the lack thereof). As such, it is probably worth doing a little additional research before diving in. I have zero experience with the Mobil 1 product, but I _have_ used RedLine fluids, and have found their technical support guys to be knowledgable and helpful. If you give them a call, they can probably give you an authoritative answer re. the additive requirements; maybe even tell you if the Mobil 1 product will be acceptable for your application. Hope this is helpful.
ByeBye! S.
Steve Jernigan KG0MB Laboratory Manager Microelectronics Research University of Colorado (719) 262-3101
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