That depends - If you think the Gen 2 trans is a 'lifetime, maintenance-free' thing as Ford advertises, then you may find it's 'lifetime' is less than 100K. But, if you drain and refill all the fluid in it (not easy to do, I'll admit) every 25K or so with a quality synthetic ATF, I'm thinking (hoping, really) it may last several times that long. Nothing lasts forever, but well maintained things tend to last longer than others. It is a shame Ford made it so hard to service - No dipstick and not even a fill port to add fluid, but a determined owner can find work arounds for those omissions
Don