Auto Trans slipping in Sport mode 1-2 and 2-3?
 

So I got this car last year and this year I started driving it hard on back roads and stuff a lot. It was originally on its factory fill of ATF less than 50k miles, though I flushed it with synthetic and it didn't fix it.



Last week it got really hot (90+) while I was driving and the car started shifting funny. Normally the shift light turns on for a split second and the shifts are crisp. But the car started over revving or something, and the revs would drop a ton on shift. When the car would cool down, it would get better. But it gradually got worse so I took it out of sport mode and drove it normally until I could get the trans flushed.



The A/T Temp light never turned on on the dashboard.



I had a similar issue in a previous car and a trans flush using synthetic fluid fixed it, so I had the trans flushed. However, it's still doing it, even when not super hot. Basically I can reproduce it now by pulling off on the shoulder of the highway, putting the car in Sport Mode, then waiting for a gap in traffic and flooring it. It's noticeable from 1-2 and from 2-3 it's really bad. Like the light turns on and it kind of revs, dies, revs, dies, then finally shifts and the RPMs dropped.


I'm worried that I burned out the clutch packs or something. Does anybody know what might be going on?

How did you “flush” it? (hopefully not a real “flush”)
What fluid did you put in specifically?
What mods do you have?
An atf cooler would have been wise before beating on her.

Maybe the Automatic Transmission Control Module is acting up?