GM TSB for 15-20 6l80 Transmissions static.nhtsa.gov/odi/tsbs/2021/MC-10207911-9999.pdf
Here's a quick DIY on how to extend the life of you GM transmission by performing the GM TSB 21-NA-199
Cost about a $75-$100
Here are the part numbers: 5.3L with the 6l80 6-speed: 86774933 Superseded by 85585333 Amazon link: amzn.to/3V5Qiyy
Range AFM disabler: amzn.to/3ZirxSb
NOTE 1: If you have a 2015, you can swap the "guts" from the 85585333 into your current thermostat housing since the 15 has different lines
NOTE 2: The TSB is specific to the 6speed, the 8-speed 8L90 is not mentioned however part number " 85585333 " on most part websites says it fits both the 6L80 and 8L90.
If you have successfully insta...