Question on a A904 with photo

"The 64-65 904's had 2 holes in the filter because the tranny had 2 fluid intake ports on the bottom of the valve body—one for the front pump, and one for the rear pump. If you use a 1-hole filter on a '65 or earlier trans, you'll starve the rear pump, which will begin to whine as it wears." SlantSixDan
Posted on slantsix.org
http://www.slantsix.org/forum/viewtopic.php?p=72996&highlight=#72996