I sent Mobil a email asking them this question and here is the dumb reply I received. I guess if you call the 800 number listed, maybe they might tell you something. I wanted to reply back that I knew it was not published, that is why I was asking the question.
On Nov 24, 2009, at 12:53 PM, ExxonMobil wrote:
The TBN is not published for this motor oil.
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Thank you for choosing ExxonMobil products.
If you need further assistance, please contact ExxonMobil at 1-800-ASK-MOBIL
MJ