How do you remove accumulator cover from transmission 4L30E?

Simple, push the piston in slightly (there is a special tool available, borrow from the dealer?), remove the circlip, then start the vehicle. Put the vhicle in gear with the brakes applied and rev the motor slightly. The resistance against the brakes (if the vehicle is off the ground..) will cause the line pressure to build and pop the accumulator cover out. This is a messy one-person, no special-tool, kind of operation.. but it works 90% of the time. If the cover remains intact, you are left with either borrowing the tool or prying it out. If you attempt to pry it out, make triple sure you do not scratch the accumulator bore or no amount of new accumulator seals and four letter expletives will fix your leak!