With normal use and proper maintenance, what would you say is the average life expectancy of an automatic transmission?

Would it be realistic to expect a typical 10-year old vehicle with AT to still be reliable and operate properly?

The reason I'm asking is the tempting price of early 2000s Ford Escapes, with the 3.0 V6 XLTs in particular. They seem value for money on paper with leather seats, a sunroof, 4X4, and modern safety features for around 250K. It seems that Ford only released AT versions so I have no choice. This would be my first AT if ever I decide to push thru.

Gas consumption aside, can I expect trouble-free ownership or will I be buying a money pit?