This cover screws into the front cover and seals the port access hole in front of the CP3 pump gear and nut. It has a 3/8 drive ratchet indentation for easy tightening. We've seen these covers melt, crack, or get broken from over tightening.
Some of these plugs or covers say 4935282 on them.
This also replaces part number 3957463.
Includes sealing o-ring.