Your question is about an 03 v8 and
You posted this in the Pre-2005 v6 thread.
Not that I care, but posting in the 99-04 v8 section might help you get a better idea of the tranny since the majority of users in that section own a similar car.
To answer your question, yes and no.
Life of an engine/transmittion does not simply go by the amount of miles on the car. The maintenance and current performance of the car is what matters. How much are you paying for the car? Change the fluid and filter and a reputable shop can inspect the tranny at that time. A brand new tranny could last 90k or 400k I wouldn't stop you from buying a car just because it has 140k on it.
how well does it run, go threw each gear and feel and listen