The screen talked about is above/under the finned plate on the bottom of the overdrive and protects the pump from large particles that may occur.

However, the screen has such a large mesh it probably will not stop enough fluid to cause your no overdrive occurence. Even if the magnetic catch strip breaks loose and somehow gets pulled against the screen.

The fine mesh filter under the plug does clog and cause a no overdrive situation.

Since you indicate all gears except OD and have reverse that does not slip, my gut reaction at this time is at some time in this process, you will have to pull the overdrive and replace the actuating piston seals at minimum. Hopefully nothing beyound that.

The only way to know for sure if it is a clogged filter that is causing your problem is to remove it and clean it. It will probably take you more time to make the tool than to remove the plug.

Duane