tmc 379 then overhaul?

2003 is a 6nz.....anything TMC has at this point would be an Accert or worse lol....apples&oranges...and to the op...be sure it is a 379.....they actually had mostly 378s....w/a small amount of 379

A pre-emmision Cat w/one set of hands on the wheel wouldn't scare me much@800k...w/good oil samples....but a fleet cat w/numerous drivers&way overextended oil change intervals better sell cheap enuff to inframe...BEFORE I put it to work.....

 

But wait, you didn't mention those "high" priced filters................

 

Don't discount the FLD classic. It's like the Honda Davidson of the trucking world...

My best advice, no matter what truck, 2002-3 or older. Gotta be careful with the 2003 and newer. EGR then DPF and DEF. Next acronym might as well just be $<!.