Originally Posted By: d00df00d
Motorcraft SAE 75W-90 Synthetic Axle Lubricant. Recommended by bdcardinal here on BITOG. No idea how good it is, but nothing has made noise or blown up so far. :]
That's pretty much all we can do, barring spending a ton of money for sample analyses or getting a bunch of similar enthusiasts together to perform end-of-life tear-down analyses of same car, similar driving and maintenance, though that would undoubtedly produce questionable data, and by the time it was provided, newer better oils/formulations would be out!
So, the only thing we can do is base our gear lube purchase on conjecture, spec's, and verify whether it makes any noise or blows the pumpkin off the back of the car!
Originally Posted By: IveBeenRued
Amsoil Severe Gear 75W-90 in my Subaru.
I'm curious to know why you went with the Severe Gear in the Impreza?
I used Motul Gear 300 in my previous '08 STI with the Torsen in the rear, but don't think I need anything nearly as robust for my new Forester. I can understand wanting to put in the best, but I also don't want to use a gear oil meant for high-torque, heavy load applications, and end up losing even a little bit of fuel economy for effectively no benefit.
Well, I guess choosing a truly synthetic gear oil WOULD have a benefit over, say, something like Coastal gear oil, in that it most likely protects better without the increased windage and flow losses...maybe.
Take this for what it's worth, but when I spoke with the guys at Redline about gear oil for my STI a few years back, they said that the shockproof was over-kill, and that their lightweight would make more sense, even with the occasional auto-x and track days I said I planned to take part in.
/digression
