Mixing viscosities

Anonymous-0 · Mar 24, 2010

Need to top the tranny lube in my MD. It currently has (I think) 80/90 in it. I have straight 140 on hand. Is is OK to use this, or do I need to buy more 80/90?

Janicholson · Mar 24, 2010

Go ahead, there will be only the incremental increase in viscosity. Jim

mkirsch · Mar 25, 2010

If you mix the two oils, you'll cause a chemical reaction that will change the oil into an extremely caustic gel. It will bubble and smoke as it burns through the bottom of your tractor, the floor of your shop, and proceed to burn a hole clear to the center of the earth, and the rock monsters will escape to the surface and kill us all! Don't do it!

Seriously, it's all oil. If you mix two different viscosities, you will end up with a viscosity that's an average of the two oils. For example, if you add a quart of 140 to three quarts of 90, you get a gallon of 102.5, for all intents and purposes.

With an old M that's seen countless hundreds of miles of running up and down fields, a little thicker oil will not hurt a thing.

sflem849 · Mar 25, 2010

Like they said, you'll be fine. There is a 90% chance that it will all leak right back out anyhow. These things only need about half of the oil that they call for in the book, esp for most light duty users on the forum.

Mixing viscosities

Anonymous-0

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Janicholson

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mkirsch

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sflem849

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