I wanted to add that there are actually 2 pans in the tranny - the larger covers the filter - there's a smaller pan (adapter pan) up front that covers the tranny solenoids. Best right up I've seen was done by Joe Black:
http://www.antiquecaterpillar.org/vx...l/4L30E_01.asp

Call around and ask for a tranny-pan filter kit for a GM4L30E- comes with both gaskets (pan and adapter pan) plus the filter - runs right at $50 and the gaskets are shrink-wrapped to cardboard so they come flat.

-- John