Random Tcc Lockup Issue

[Michiganvmax]

i recently took my 06 crew vmax to florida on vacation, vacay was great, truck did awesome 17.1 mpg's at 80 mph. I did notice that after a while atleast 150 miles if i went 80mph the trans would occasionally come out of lockup it would always reengage but not for atleast 3 miles i didn't do it all the time, more often in hilly areas, if i went 70mph it would never occur, i could not pinpoint when it would do it, i couldnt predict it aside from the variation in speed.

this truck at 80 is turning 2500 to 2600 rpm with the 4.10 and 285 50 20 tire, i know these trucks have to small of a factory trans cooler, so i need to get a bigger one, but i have made alot of valvebody changes, vette servo, sonnax afl, sonnax boost valve, and shift kit. the trans is original, the truck is strong and i know there has to be a weak link i just thought the factory carbon woven lockup clutch in the converter was bulletproof. So my question is this a programming issue [ the truck has had all the factory trans features turned off/ reprogrammed] or do i need a new converter