I put the MagHytec pan on today and changed both transmission filters.

After replacing the filters, i decided to cut open the flat filter to see how dirty it was. To my amazement, it looks as clean as a new one. I didn't see anything really in it. I know that some of the new cars are coming out with no transmission filter.

Anyways..my question is...I'm at 40K miles right now, and changed both filters. Should there be any need to replace the filters again at 90K? or 120K? Now that i have a drain plug, and after seeing the flat filter looked new... i'm thinking that every 15-20K just draining the 7 quarts of tranny oil...and refilling.

I've heard folks say that if you want to keep a 45RFE transmission alive, you must change the fluid often. Not that it filled up with metal shavings, but because it lost it's properties of lubrication causing premature failure from excessive wear.

 

Depending on the year, you may have been premature on the change. The service interval is 60K now.

 

Filter change...I'd say a fluid flush should be done at 50kmi and a filter change done at 100kmi. Unless your being excessive on towing or live in the desert, then cut it down to 40/80.
The fluids that are out these days keeps the internal components very clean and really disintegrate any sludge or grime that would otherwise get caught up in the filter or valvebody.
You are premature, but that's the best line of Preventative Maintenance there is! That is one reason I rarely ever have troubles with my toys!!!