Mixing Gear oil?

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Do you guys see any problems with mixing in equal proportions Shell Spirax EW 75w 90 and 80w 140? So I would be looking at an end result of 77.5w 115.
Second question if I were to run straight Spirax EW 80w 140 grade down to 0 Fahrenheit. How long would it take to get the oil to the outer bearings in the rear axle? Here is a link to the product.
http://www.shellusserver.com/products/pdf/SpiraxEW.pdf
I plan on running this in my Dodge with Auburn LSD and 4.10 gears.
Thanks.
 
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I love the math logic, but Id say gear oil or car oil, is a chemistry equation , u got to balance the equation,,it molecules and such and electrons, and on and on,,,,see a chemical engineer and see what he says,,,,,,,,,,,,,,I dont mix auto oils either
 
p s I worked in a lawnmower store once,,folks would come in and say they wanted a red wheel like on that mower over there,,u b the judge
 
You can mix them, but you will likely end up with a 90 weight oil.

AT 0F the oil will already be at the bearings. 80W140 is fine for low temps, a 75W140 would be better
 
Ok.I thought I'd get a reply like that on mixing. Do you have an opinion on my 2nd question. " If I used straight Shell EW 80w 140 down to 0 degrees F. How long would it take to get oil to the rear axle outer bearing!
 
Originally Posted By: Bluestream
You can mix them, but you will likely end up with a 90 weight oil.

AT 0F the oil will already be at the bearings. 80W140 is fine for low temps, a 75W140 would be better

Thank you. So the 80w will have almost instant lube at the rear axle bearings. I want to run mineral oil. Tried synthetics they did not work very good in my unit. Amsoil grinded like [censored] even with 2 bottles of additive and RL 75w 90 was loud.
 
What vehicle are we talking about? If it has a solid axel, the oil will be at the bearings at all times; it does not need to flow like in an engine. I assume you want the thicker 80W140 to keep the noise down?
 
It should not matter if they are well formulated. A lot of 140W gear oils are poorly formulated and do not behave as they should in cold weather. As to the mixing part I was never one to have to mix weights but growing up I could never find enough gear lube to do all my dif's,manual trans. and transfer case in one brand. I always had to use 2-4 different brands often having to mix brands in the wame weight and I never had an issue.

The main issue is what does the diff. need for the way you use it. If you are towing and the OEM calls for a 140 for towing it is best to pay some attention to the recomendation. IF not towing then generaly youc an use much lightr gear lubes then recomended and no harm. This is especialy true with synthetic gearlubes.
 
I asked the exact question to the Valvoline tech support people. They said no. gear oil doesn't work like that. The additive packs are completely different.
 
Originally Posted By: PT1
I asked the exact question to the Valvoline tech support people. They said no. gear oil doesn't work like that. The additive packs are completely different.


I aske Redline if I can mix their 75W90 and their 75W140, and was told yes but I would end up with just a 90 weight gear oil
 
Yes I am using 80W 140 to reduce gear noise. I have a Dodge Ram P/U. The rear LSD has been changed to Auburn with 4.10 gears. So Dodge recommendations of 75W 140 synthetic do not apply. I do tow snowmobiles long haul at high speeds for about 8 hours at a time. Auburn recommends 80w 90 mineral oil. So that is what I was using. I seemed to have developed a slight gear noise during the summer and have noticed that the noise is much quieter with the colder temps setting in.. So I know a thicker oil will quite it down some more. Hence me trying to come up with heavier mineral based viscosity gear oil. But not straying to far from the 80w 90 recommendation. A mix of the two EW’s seemed perfect. I will just continue on with 80w 140 that I have in it now and drive slow when cold to give some extra warm up time. I know the EW 80w 140 has pour point of -38F. I was just wondering about the outer rear axle bearings. I did not want them oil starved when I first drive off in the morning. By the sounds of your replies I should be ok.
Thanks guys .
 
Mixing the 2 would give you a 110wt if you get the ratio correct.

Amsoil, Klotz, JoeGibbs.... I believe all sell 110wt gear oils.

I would just thumb my nose at the Auburn recommendation and use the 75w140 full synthetic. The full synthetic will flow well, and most 140wts will shear into a 110wt over time anyway. And, if you work the truck, you need the 140wt protection.
 
Originally Posted By: unDummy
Mixing the 2 would give you a 110wt if you get the ratio correct.

Amsoil, Klotz, JoeGibbs.... I believe all sell 110wt gear oils.

I would just thumb my nose at the Auburn recommendation and use the 75w140 full synthetic. The full synthetic will flow well, and most 140wts will shear into a 110wt over time anyway. And, if you work the truck, you need the 140wt protection.



I don't believe anyone manufactures a 110 weight mineral based gear oil (if they did I would be using it!!).
Some people concerned about their diff's warranty (and even proper functioning), don't have the luxury of "thumbing their noses" at manufacturers' fluid reccomendations.
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