GMC: FLARE AND OR HARSH 2-3 SHIFTS. THIS CONDITION MAY BE CAUSED BY LEAKING 1-2-3-4 AND 3-5-R CLUTCH FLUID SEAL RINGS (230). MODELS CADILLACS, CHEVROLETS, GMC, HUMMERS, PONTIACS. EQUIPPED WITH 6L80 (RPO MYC) OR 6L90 (RPO MYD) AUTOMATIC TRANSMISSION. *PE