Originally posted by 302/Z28
I do not disaggree with what you are saying about ATF, but I will relate a story that happened to me. I work for DuPont and one of the products we make is an elthylene elastomeric rubber, One of our customers is Castrol. They use our synthetic rubber as a viscosity modifier in their motor oils. One time we got the rubber a little off spec and no one caught it in the lab. It caused some problems at Castrol when they ran a quality check on their motor oil. A Castrol engineer came down to help iron out the problem. We had a long conversation on motor oils and ATF. He told me that ATF is the most engineered lubricatant known to man. He never mentioned that it is mineral oil.
Just for thought
Funny I had just the opposite experience, I had done some contract work for a major oil distributor here in Wpg. and I needed some dye to find an oil leak in an accumulator tank system (16 tanks) for another job, they were all interconnected and the leak was not visible so I decided to ask these guys if they had some sort of tracer or marker I could use (I was looking for an ultraviolet light visible marker actually). I was taken into a large warehouse where a guy opened a paint cabinet which held a few different 1 liter cans. He gave me a can that said "Red dye#1" or something like that and told me to give it a try. The liquid inside looked like mercury but when added to oil looked red or orange depending how much you added, it was very potent stuff and you didn't need much to tint an oil. I added 1 ounce to a 100 gallon accumulator tank and it was blood red after.
During our conversation he related that this was the same stuff they use to tint ATF fluid, he said you add so much for Type F and so much for Dextron. There was another bottle of additive agent they added for auto transmission use but straight tinted mineral oil is what you get when you buy plain hydraulic oil. Since this was the guy who did this at the plant I believe what he said, all he did all day was blend the oil and bottle it for store sales.
Sure enough when I experimented with different amounts of the dye I could get any color from light orange to blood red depending on how much I used. He also said that straight mineral oil does not foam, it's only when you add detergent will it foam hence the need for an additive package added to the basestock.
When you think about it why do you need anything other than straight mineral oil? Radial aircraft engines run on straight mineral oil and use a sludge tank to trap stuff that gets into it, detergent just keep the dirt in suspension so it can be filtered out and will stick to the metal sufaces inside the engine instead of falling to the bottom. Just like your dish detergent.
The detergent package is what makes the mess. Try it yourself, take some ATF fluid and throw in some dirt from your garden and give it a shake, then take some straight mineral oil and do the same. Let it sit for a day and see what happens. You will see the dirt stick to the sides of the container and most will stay in suspension turning the oil murky, the straight mineral oil will settle out the muck on the bottom and stay clear. I'm sure there is some kind of seal conditioner added to the additive package as well but in the end what your buying is straight mineral oil with a little dish detergent and some paint thinner added for seal swelling and a little kerosene/diesel fuel to keep the foam down. Companies like Dupont spend millions of dollars designing molecules that have certain properties to meet certain specs but in the end it's added in minute quantities to straight mineral oil and sold at an extraordinary profit. I seriously doubt it makes much difference in the end.
Hope I didn't burst any bubbles out there. My best advice is change the oil regularly to get the gunk out and forget the fancy oils although I do think synthetic based oil is superior in every respect, now if only I could find some straight castor bean based synthetic oil by the barrel for a reasonable price. I would use it for everything from brake fluid to motor oil.
They can keep their expensive oil additives, I would rather change it more often.