One more thing, I would recommend buying a skip shift eliminator. This gets rid of the annoying 1st to 4th shift requirement during slower speeds.
Obligatory not my car but I’ve been seriously considering a Chevy SS.
This ~$20 part and a few minutes work disables the factory 1-4 skip shift without throwing codes
You may not have hurt it, but the potential is there to really fuck your trans. I would not suggest that you do it any more.
You have 2 options to get rid of it.
A tune. This will void your warranty, but you'll eek out a bit more performance.
Skipshift eliminator. 20 bucks on amazon, plugs in under 10 min.
Link to eliminator:
SLP Performance Parts 21008 Skip Shift Eliminator https://www.amazon.com/dp/B002WBRRHE/ref=cm_sw_r_awd_2030ub0TH1RNK
Please don't keep doing it. Zl1 is too nice to mess up!!!