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Discussion Starter #1
Hey guys,

I went to SEMA last week and took the opportunity to ask Royal Purple about the cold weather shifting problem most people in the north experience.

The rep said they are working on a "thinner" GL-4 oil for the Winter months to better complete with Redline and Amsoil. He said it was a common complaint, and that Royal Purple recommends that people use there 10W40 motor oil during the Winter months. He said it uses the same base.

This sounded fishey to me, so I just walked away.

Does this sound right, does anyone use Motor Oil in their trans? I know there are Transmissions out there (mainly Hondas) that use motor oil, but I've never heard of that in a GL-4 trans.
 

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I don't claim to be a lubricant chemist, but that's some advice I wouldn't take. If gear lube and motor oil were interchangable, why do they make both? They serve very different purposes. Go with Redline MT90 if you're looking for a change..it's the best stuff I've ever used.
 

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I read something (I think it was on the back of a Redline bottle) that 75w90 trans fluid is the equivalent of 10w40 motor oil.

I forget where I read it, so I won't say for certain, but I'm 85% positive it's true.


BTW: The reason they don't sell oils as universal is because they have a competent business model. More opportunities for price discrimination and higher profit margins with multiple products. Costs are kept down because it's all essentially the same stuff.

BTW part 2: Royal Purple has been proven to be crap anyway. Go with Redline, Amsoil, or Schaeffers.
 

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Discussion Starter #4
Oh, I already run Redline. I was just posting this because I was one of the members that had that cold weather problem with their Gear Max fluid.
 

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QUOTE (xtmesisx @ Nov 9 2009, 01:05 PM) index.php?act=findpost&pid=1615301
I read something (I think it was on the back of a Redline bottle) that 75w90 trans fluid is the equivalent of 10w40 motor oil.[/b]
That makes no sense. Viscosity is viscosity, regardless of the intended application. Either the viscosity is 10w-40 or it is 75w-90; it can't be both.
 

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QUOTE (jd42 @ Nov 9 2009, 03:03 PM) index.php?act=findpost&pid=1615345
That makes no sense. Viscosity is viscosity, regardless of the intended application. Either the viscosity is 10w-40 or it is 75w-90; it can't be both.[/b]
Yes it can. Gear oil viscosity and motor oil viscosity are rated differently. You lose. ;)

QUOTE (redlineoil.com)
* MT-90 75W90 GL-4 Gear Oil
* 75W90 GL-4 gear oil (similar to SAE 5W40/10W40 engine oil viscosity)
....
* Satisifies the gear oil viscosity requirements of 75W, 80W and motor oil viscosities of SAE 40, 10W40, and 15W40[/b]
Source: http://www.redlineoil.com/product.aspx?pid=46&pcid=7
 

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QUOTE (xtmesisx @ Nov 9 2009, 10:56 PM) index.php?act=findpost&pid=1615484
Yes it can. Gear oil viscosity and motor oil viscosity are rated differently. You lose. ;)[/b]
Ah, but learning something new turns it into a win :)

My error was assuming the oil "weights" were a measure of viscosity. After a little research, I see the numbers are viscosity grades, as defined by the SAE. As xtmesisx states, motor oil and gear oil are graded differently (SAE J300 vs. SAE J306).

So, what Redline is saying is that a 75w-90 grade gear oil has (effectively) the same viscosity as a 10w-40 grade motor oil. Now it makes sense. :D
 

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QUOTE (jd42 @ Nov 9 2009, 11:37 PM) index.php?act=findpost&pid=1615499
Ah, but learning something new turns it into a win :)

My error was assuming the oil "weights" were a measure of viscosity. After a little research, I see the numbers are viscosity grades, as defined by the SAE. As xtmesisx states, motor oil and gear oil are graded differently (SAE J300 vs. SAE J306).

So, what Redline is saying is that a 75w-90 grade gear oil has (effectively) the same viscosity as a 10w-40 grade motor oil. Now it makes sense. :D[/b]
Well if you're not going to get defensive and yell at me for being an asshole, where's the fun coming from then?
 

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QUOTE (xtmesisx @ Nov 10 2009, 02:49 PM) index.php?act=findpost&pid=1615653
Well if you're not going to get defensive and yell at me for being an asshole, where's the fun coming from then?[/b]
I didn't think you were being an asshole. Maybe your post had the potential to be a bit more polite, but I made an incorrect statement and you called me out on it. There's not much there for me to be defensive about.

I should have done my homework and made sure I understood the API grading system. Being wrong motivated me to learn something new, so it's all good.
 

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QUOTE (jd42 @ Nov 10 2009, 05:26 PM) index.php?act=findpost&pid=1615695
I didn't think you were being an asshole. Maybe your post had the potential to be a bit more polite, but I made an incorrect statement and you called me out on it. There's not much there for me to be defensive about.

I should have done my homework and made sure I understood the API grading system. Being wrong motivated me to learn something new, so it's all good.[/b]
STOP BEING SO REASONABLE!!!! :laugh:

For the record, the rest of the Internet could take a lesson from you. You're the man.
 
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