I have a 2018 Chevy Tahoe 5.3v8 LT with about 80,0000 miles. I bought it used at 75,000 miles and have changed the oil and spark plugs but I’m not sure what other maintenance it’s had. Iv been told about tahoes transmission problems and have been told I need to change my fluid before my trans starts slipping. I need to know what fluid to use and if the gasket is reusable.