Does your 6l80 do this?

[jcsws6]

So I've been frustrated with a single issue about my cars shifting since a few days after delivery. The car doesn't drop to 1st gear when going full throttle above 20mph (factory 1st read line is 36). I've tried it in every mode and it makes no difference. A hand full of times it has downshifted correctly and performs like I would expect but that's maybe 1 out of 20. I can use the flappies and get it drop with no issue but I can't understand why it doesn't do it on it own. I've tried diablo and Scts canned trans tunes and they do nothing for this. I've got a buddy with a 6l80 in his truck and he has the same ambiguous shifting issue. Maybe it's a common thing?

Does anyone else have this issue?

[SSlow5thgen]

Yea it won't above 20
First gear ratio is just too low

[jcsws6]

Originally Posted by SSlow5thgen

Yea it won't above 20
First gear ratio is just too low

But redline in first is 36 and you can manually do it without issue. This doesn't make sense.

[Slowhawk]

You can fix it with a tuner, most canned tunes just won't touch it.