I have a 2011 Express. I have been the sole owner and never really have abused it, like I did thing in my younger years.
Anyway, last August I was driving slower for a long period of time and after coming to a stop sign, when I took off the shift from 1st to 2nd was a jerk. A hard jerk. It did that for most of the day.
Got home and drove around the next day and it shifted just like it always had.
Then one day it started shifting with that jolt between 1st and 2nd again. Where ever I was going I parked and did what I was there to do and it worked fine as ever.
1st thing I did as soon as I could was change fluid and filter on the transmission. Seemed to work for awhile and then started it again. Then was ok for a long time.....then it wasn't. This is how it has been going since last August.
Anyone have any ideas?

 

mileage?
Have you tried searching the forum?
https://chevroletforum.com/forum/sil...nd-gear-52050/
https://chevroletforum.com/forum/sil...nd-gear-65530/