2005 Yukon XL Denali tranny whine while towing/braking?

I run the Tru-Cool Max 40k as well. It became necessary after my grill guard changed the airflow into the stock cooler.

441,000 miles on my transmission, zero work done to it, besides a couple filter changes early on. Now that I have the tru-cool max, and a Magnefine filter, I simply use the "Bucket Method" to do a full fluid swap every 100,000 and change the Magnefine. Last time my pan was dropped was at ~170,000 miles.