The OE plastic 3-tab washers break or melt under normal operation in listed GM TH180, TH180C (3L30) and 4L30-E transmissions. Sonnax 3-tab bimetal thrust washer and shim kit 54701-03K replaces the OE plastic washers in both pump and center support locations.
The Sonnax thrust washer kit cannot be used to replace late style no-tab thrust washers.