I agree with the above about the check valve, completely remove it before calling it a day.

 

Miy trans went last year with the shrunken seal syndrome. Had it rebuilt with kevlar bands, heavy duty clutches, and a billet reverse servo. I also added the Transgo Jr. shift kit. You will need to drill another oil hole through the main shaft to insure better oiling for overdrive. All instructions for this are in Transgo kit. Maintained properly your tranny will be alot tougher and last you years! Good luck with this project.

 

Pump isnt pulling oil throught the filter, so there are just a few things that will cause this problem, but since you changed the filter that is eliminated....It seems to me that the pump broke.....could of just sheered the ears off the lugs...thats the usual suspect....

Brian