TC...TC-W, or TC-WIII; Yes, you're right, Ben. Thanks for correcting my mistake.
Actually, if the oil just said TC on the label, I'd probably pass. I think that's the oldest, least restrictive spec. Without any spec at all, it might be good oil, but I'd suspect that the bottler hadn't taken the effort to get it tested for a reason besides cost (somewhere I've read 75 grand per batch/formulation) and was perhaps a little "too hungry" and maybe willing to slide on quality control. Many labels clearly state that their product will be supported by the oem's warranty program...but you know that the major names will not be pulling down their shingle to avoid problems caused by trying to slip something by....