I tow with my 2011 Tahoe with the same 6 speed trans and 3:08 gears. Does great. My 5.3 has the AFM (or DOD, it’s the same thing) and it works great. We are nearing 140k. I run fully synthetic oil only and I change the oil when the OLM gets to 50% because I tow a lot. (My camper and my father in laws big pontoon boat)
3:27 would pull better than my 3:08 but with the 6 speed my 3:08’s do great.
My TT is 7,000 ish lbs loaded and 11 ft 2 Inches tall.
Trans temps rarely top 180° and pulls like it’s on rails. Love my Chevy.
Thanks!
Jeremiah