200-4R troubles.......Need help diagnosing..........Please!

[79cutlass]

I switched my lines to run just through the aux. trans. cooler and it never got above 180 so far. And when it does it goes down to 160 or even less. This is good news for me. It seems like it shifts later than it normally would sometimes.(I don't have a high-po govenor so it doesn't redline before i shift) But one time it redlined and wouldnt shift until i let off the gas a little. But it seems to be ok most of the time.