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

[OfficeLinebacker]

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?

[86TOYO2k17]

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.

[humfrz]

Maybe the Automatic Transmission Control Module is acting up?