Quote Originally Posted by joecar View Post
I don't have any 6L80/90 to experiment with or otherwise destroy...

These work different than the 4L60E/4L80E in that the components are sequenced electronically rather than hydraulically, and the trans calibration contains timing relationships which are critical.

Some people have figured out how to tune these.
Wished someone would do a 6L80 tuning tutorial.

Bill