I got 96K on mine, still shifts well. The key to tranny longevity in any car is to periodically CHANGE the fluid regularly. In our case, it means draining and refilling (filter is inaccessible).
The owners manual says to do the drain/refill/drain/refill procedure every 30K. Should get out up 6 quarts of fluid.
Also add a bottle of Lubeguard. Heard its pretty good stuff.
