99fxst99

2016 Suburban Z71 with 105K miles
When cold the transmission acts like it's in an enhanced tow mode. When decelerating it downshifts hard, like manually downshifting. This continues until I stop and shut it off. As long as the trans is warm the rest of the day it is usually OK, but if it cools to ambient temp the situation returns.
Any thoughts?
Thanks!

repairman54

Needs a full all 4 code families code scan. Not just P codes but all 4. That's step one on a modern vehicle to see what may be going on.

99fxst99

Thanks. It goes in for oil change soon, I will have it scanned.