|OK8N said: (quoted from post at 13:51:55 12/19/11) Thanks for the clarification, although I don't think I have a hang up about the term "mineral oil" - just being lazy. Folks around here differentiate 90wt transmission mineral oil from UTF and gear lube. When I ask for mineral oil for my tractor transmission, this is what I get:|
TOH said:<EM> - So any conventionally refined UTF is in fact "SAE 80 mineral oil". - </EM>
I was not aware of this. My understanding was that many UTFs were lighters oils, as reports of increased UTF oil leakage by some "N" owners who have used both UTF and GL1 "mineral oil". I've also read that oil which conforms to specification M2C134D (Ford-New Holland spec for "N" tractors) is equivalent to an SAE rating of between 40-50. Obviously I'm no tribologist.
First off I wasn't picking on you in particular - your post just happened to be the last of many that finally elicited my comment. I'm not a tribologist either but you don't have to be one to understand how the grading
system works. And it does not work like the vast, vast majority of people think.
The SAE viscosity numbers are viscosity grade labels
not units of measure - sort of like light, medium, and heavy. Sometimes I think the SAE would have been better off if they had actually gone that route instead of using numbers. And to make matters worse there are different grading standards for gear oil (SAE J306) and motor oil (SAE J300). The J300 motor oil grades are designated SAE 20, 30, 40, 50, and 60. The J306 gear oil grades are designated SAE 80, 85, 90, 110. 140, 190, and 240. And while the motor oil and gear oil grade numbers
do no overlap the actual viscosities
associated with those numbered grades do. Here is a subset of the full specifications - if you want way more detail try my little monograph on the subject: J300 Explained
SAE J300 motor oil viscosity grades:
SAE 30 - 9.3-12.4 cSt @100C
SAE 40 - 12.5-16.2 cSt@100C
SAE 50 - 16.3 - 21.8 cSt @100C
SAE J306 gear oil viscosity grades:
SAE 80 - 7.0 - 10.9 cSt @100C
SAE 85 - 11.0 - 13.4 cSt @100C
SAE 90 - 13.5 - 18.4 cSt @100C
Which brings us to UTF type lubricants which are technically not a motor oil or a gear oil and as such are not tested to and don't qualify for an official API/SAE "starburst" viscosity label. But when folks - including the OEM - decide to put an SAE grade number on a UTF product for "informative" purposes they have to choose: motor oil or gear oil grade? Case in point - CNH Ambra 134G universal fluid (e.g. M2C-134D). I emailed the OEM that makes that product for CNH and the specified viscosity is 9.4 cSt @ 100C. That makes it either SAE 30 using the J300 motor oil specification or SAE 80 using the J306 gear oil specification. Two differnt viscosity grade labels but in fact the same viscosity - take your pick either one is "correct". Hence a lot of confusion. I've looked at a lot of UTF product specifications and they fall somewhere in the 9.0 cSt to 11.5 cSt range. So if you want to scare someone off of UTF tell them its SAE 30 oil. If you want to make them comfortable with it tell them its SAE 80 or 85 oil. If you want to be coldly scientific and accurate about it tell them that depending on the brand and formulation it has a viscosity somewhere in the range 9.0 - 11.5 cSt @100C. And either way it's mineral oil ;-)
TOH This post was edited by TheOldHokie at 15:22:45 12/19/11 3 times.