GMPartsGiant.com offers the wholesale prices for genuine 2021 Cadillac XT6 AWD parts. Parts like Automatic Transmission 2-9 And 4Th Clutch Piston Housing Assembly are shipped directly from authorized GM dealers and backed by the manufacturer's warranty. Parts fit for the following vehicle options. Engine: 6 Cyl 3.6L. Model Code: LUXURY X-OVER 4DOOR(GMNA), SPORT X-OVER 4DOOR(GMNA).