03 WRX MT fluid

Slight correction. Red Line 75W90NS is **not** GL-5 rated. They fudge with the part of the GL-5 specs which require friction modifiers for limited slip diff compatibility. Red Line 75W90 (which Red Line only recommends for LSDs) is GL-5 rated.

That being said, I'm using the 75W90NS. I was also using Red Line MTL in a '95 Integra for years without any problems.

Redline does claim GL-5 ratings for both the NS and regular 75W90. You may be right about the spec, but then Redline has a problem. I used the NS for 50K, and in fact just drained it yesterday and changed to Valvoline Durablend. Although I didn't have any complaints about the NS for a long time, I now find that the shift quality is much improved with the Valvoline. I think the Redline may have thinned or otherwise changed over time causing the shift quality to be less than optimum although I can't fault its value in protecting the tranny- when drained after 50K of use, there was hardly anything at all on the magnet. I also have used the MTL in a previous vehicle, that stuff was magic in transmissions that could use it. Unfortunately the newer Subarus can't.

Before I hit my post, I went to the garage and took a good look at my bottle of Red Line 75W90NS. Nowhere on the bottle does it say that it is GL-5 rated or even meets the GL-5 standard. The wording on the label is, "Recommended for API GL-5". The current Red Line website says "GL-5 type". Red Line says their 75W90 is OK for use in transmissions, but that their 75W90NS is preferred because the synchros engage better without the friction modifiers.

It's much like their recommendations for MTL and MT-90. Those aren't API S- rated oils or Dextron-II ATF, but are recommended in place of those fluids in manual transmissions.

BTW - I plan on replacing the gear oil every 30K miles anyways.

From the "Tech" page on Redline's site-

"75W90 NS, 75W140NS - GL-5 lubricants which do not contain the friction modifiers for limited-slip hypoid differentials."

I'll have to go check a bottle of the NS more carefully.

It is possible that Redline has not "paid their money" to API for certification even though it easily meets their specifications. This is the case with many Amsoil blends.

Thanks for the info. Does it quiet it down at all ? One issue i have is a crunch going from 3rd-4th when shifting at high rpm's, same when downshifting from 5th -4th depending on how fast i am going. And a whine in

1st, say i go over a speed bump in my apartment complex, leave it in first and coast down to the next with the clutch in. And an occasional problem going into reverse.

differentials."

wording

That can't be it. The API doesn't have anything like the "Engine Oil Licensing and Certification System" (EOLCS) for gear oils. I think all they do is publish their standards and let the gear oil makers do what they want. There is no "donut" or other license for the API gear oil standards. I'm thinking 75W90NS really doesn't meet ALL of the API GL-5 standard because the friction modifiers for LSDs just isn't needed in the transmission.

differentials."

wording

That can't be it. The API doesn't have anything like the "Engine Oil Licensing and Certification System" (EOLCS) for gear oils. I think all they do is publish their standards and let the gear oil makers do what they want. There is no "donut" or other license for the API gear oil standards. I'm thinking 75W90NS really doesn't meet ALL of the API GL-5 standard because the friction modifiers for LSDs just isn't needed in the transmission.

differentials."

wording

That can't be it. The API doesn't have anything like the "Engine Oil Licensing and Certification System" (EOLCS) for gear oils. I think all they do is publish their standards and let the gear oil makers do what they want. There is no "donut" or other license for the API gear oil standards. I'm thinking 75W90NS really doesn't meet ALL of the API GL-5 standard because the friction modifiers for LSDs just isn't needed in the transmission.

"Paid their money". Ha! $825 per year!

Yes, $825 per year. The cost of about 100 quarts of Amsoil's finest. Testing the oil to make sure it meets the specs is the expensive part. The actual API licensing cost is insignificant. The "extreme cost" of API certification is BS that the Amsoil droids spewed here for years to try to explain why their oils weren't certified.

Chances are, Redline and Amsoil both screw around with their formulations too much, and are too cheap to test. Sure, they might have tested some formulation in the past to ensure it passed all the tests, then "grandfathered" or "read across" new ones to convince themselves that their new formulations rate. But sometimes it doesn't take much to screw up the performance of an oil.

You'd never catch me pouring an uncertified oil into an engine I cared about -- especially if it was still under warranty.

I didn't say anything about annual dues, just the certification. Yes, that is the expensive part. Regardless, Amsoil is superior to than anything else you are pouring into your engine.

The $825 "annual dues" IS the cost of the certification.

So you agree that the testing is the expensive part, and that the $825 paid to the API for certification is insignificant. So why the comment about "paying their money"? $825 is nothing. It seems to me that saving money by forgoing testing is pretty risky.

How do you know, if it isn't tested?

Oh, I forgot. You read all the testimonials and the four-ball wear tests in Amsoil Action News, right?

Yeah, it is pretty thin, when you look at all the hype, but absolute lack of certification.

Unfortunately, folks have absolutely unswayable beliefs on engine oil. Oh, particularly the guys that are making $$$ as "resellers" .

Again - doesn't matter when it comes to gear oil. The API publishes a spec. The gear oil maker/seller claims to either meet the spec or not. The API is not involved in licensing or certifying gear oil.

Red Line claims to meet the API GL-5 spec for their 75W90 gear oil. They don't claim the same for their 75W90NS gear oil. This has nothing to do with any certification or licensing issue.

Amsoil must be doing something right because everytime they are mentioned some people go over the edge. These people probably also voted for Kerry. Get over it, Amsoil makes great products and Bush won the presidency.

Who cares if we sell Amsoil, someone sells and profits from selling every kind of oil.