Thanks for the tip.
The GM radiator was 3 times the cost but definitely more robust construction.
Other owners I know got over 260K miles out of their 8.1's and Allison's so It's worth the investment.
Of the many many people I know with Allisons only know of one that died at about 150.000 miles. A split race bearing separated. Rated towing 12.500 he's been towing way, way more than that the entire life of the truck. Chevy dealer in Laughlin service manager told me they've never seen a bad one.
Lucky to find any GM over the counter parts anymore. Got the last flip up center console avail in the USA. Truck has a rare bench front seat,, and leather at that.
We'll keep it another 100K and then it'll do river duty garaged then just launching and retrieving boats. Been the most amazing truck, it's been everywhere done brutal duty.
Those new 2019 GMC 6.2 4x4 1500's sure look nice.