Ya I just saw that rotella T in walmart, wasn't sure if it was synthetic or not cause it didn't say. I couldn't imagine that much synthetic oil for that cheap a price, so I didn't buy it. I just checked out the MSDS for the 15W40 that they have at walmart and it doesnt give any indication that it is synthetic. It looks like the 5W40 is the only synthetic stuff and its viscosity is comparable to the 15W40 triple protection (petroleum based) at 100 degrees celsuis. I'm sure that a 5 gallon pail of the synthetic 5W40 is much more expensive than what they have a walmart.

Still, $66 for 5 gal of rotella T is a very good deal.