http://www.automotiveforums.com/vbul...smission+flush
This is a link for a thread in the Aurora forum about this a while back. Maybe this will help you decide what you want to do. Maybe not, it is kinda of split between do it and not do it.
My beleif is that an older trans that has not been serviced regularly should not have the system "shocked" by a flush. Drain and clean the pan, install new fluid/filter and run it.