ok, i highly recommend you read about the cooler mods for the ATs.. you're approaching on a median time for the ATs to go if stock.. it depends who rebuilt the tranny the first time.. they should have installed the external cooly already but you knever know.. the other thing was that the replacement intenal parts needed to be modified and i don't think that many know of that..
as i recall i had pretty good power in higher bands but this ain't a v8 and my 94 is a stick so it's a bit different.. and i have never redlined it unless i forgot to shift.. LOL the reason i said all the above is because the redlining while shiftdown isn't normal.. i can see 4k maybe a bit more but not 6k.. something aint right and it maybe something easy.. i dunno.. run ecu codes.. all the info is in the stickies here or the garage.. if you don't see it, search and then ask away..