If you want to KNOW what is in a particular brand of oil for phos and zinc, the best way is to just swing by Walmart and buy a quart and then stop at your local big truck dealer and ask for an oil sample kit at the parts dept. There are a few different labs, Wearchek (sic?) Blackstone and Caterpillar are a few.
Cost, $15-20. Pour some oil in the bottle, fill out the info form and hand it back to the parts guy to send out.
In a week or ten days you will know exactly how many PPM is in that brand of oil.
Kevin.
