Letter from GMC today re rough trans & hesitation on 6.2L engines

[Ltz4 me?]

Hmmmm, interesting...

Were you having harsh shifting there?(1-2,2-3)

[Ltz4 me?]

Mine does hard shifting especially on 1st startup/ move of the day...

[lucas287]

2 hours ago, Ltz4 me? said:

Mine does hard shifting especially on 1st startup/ move of the day...

I think that's a characteristic. The 1st 1-2 of the day is always awful on my truck. Literally 100 yards later on the stop sign - doesn't do it. 

 

I'm realizing that shift quality/transmission behavior is SOOO correlated to our Virtual Torque and Airmass tables. When I'm on an alcohol mixture between 25% and 80% my trans feels awful. Clunky shifts, especially down low, hunts around, flares, just generally feels awful. When I go back to e10 all those little quirks are much improved. 

 

Someone else on here has mentioned 5 wire MAF sensor and that might be a contributing factor after all. This makes tuning EVEN more important. When you get the MAF (airflow models) dialed in, the transmission really settles down.