Hey Guys!
There has always been a myth about the transmission filter on all the models. Truth is, when you ask a dealer guy they will always say lifetime since they are never replaced in the shop. Whenever there was a major service (when the transmission service was included) the techs would always CLEAN the transmission filter in the parts washer, this after a flush and before a refill. The fact of the matter was Service Departments wanted to keep the cost of the services down so they could generate more labor and not compromise an overall price increase for the service in its entirety. Now-a-days the new Matic-S cars only have a magnetic pan en-lieu of the strainer.
Now, for a DIY job many service guys (and me included) WILL recommend a filter replacement just for the simple fact that most people don't have a good parts washer just lying around in their garage. There is also the fact that most won't/can't perform a flush. The flush is important because it will push most (if not all) particles into the strainer/filter right before it is washed. Obviously if you can’t perform a flush all of these particles are still in the gears and will eventually recirculate and deteriorate the new fluid. In addition, you get a good piece of mind feeling you did the job to completeness and change the filter out while you’re dropping the pan anyways.
Here are some links to the gasket, strainer, or-ring and crush washer, all for the FGY33:
Strainer:
http://www.infinitipartsusa.com/Infinit ... 51x04-.htm
O-Ring:
http://www.infinitipartsusa.com/Infinit ... 41x07-.htm
Gasket:
http://www.infinitipartsusa.com/Infinit ... 51x02-.htm
Crush washer:
http://www.infinitipartsusa.com/Infinit ... 01m02-.htm
Hope this helps!