It's got right around 180k, fluid looks super clean no odor or hot smell coming from the fluid or truck. I have not flushed the cooler or the lines. I haven't felt anything while driving it, not any major slips anyways. The only reason I know something is wrong with it, is the digital temp gauge had reached over 200°.
I have thought about doing the bypass to the trans thermostat.. but I just looked and I don't have the same set up as the bypass for the 6L80s in the newer 2014s and up.
I'd start w/flushing the cooler or lines then look for potential sources of heat (missing exhaust shielding, etc). Another possibility is the torque converter clutch beginning to wear and slip, causing heat to build within the unit while you're in gear...The torque converter clutch is active and functioning in gears 2-6 and so it's constantly being commanded on and off. Over time, this wears the clutch and it begins to slip.
One additional vulnerability is a sub-system within the transmission called the compensator feed circuit. This consists of the compensator feed reg valve, clutch select valves, pump (stator bushing), turbine shaft sealing ring, and all of your 'piston dams' - they all work together to release clutches when a given apply circuit is commanded off as well as manage shift feel and timing...If parts like the bushing(s), turbine shaft sealing ring and/or piston dams get worn, they're not as efficient thus require more time/duration to do their jobs...that time builds heat which shows up in the form of elevated trans temps...
Not saying you should panic but at 180k you're prob in the last 5-10% of that thing's lifespan, especially given its a pre-2012 unit...Much of what's in there now, including the drum, pump stator, 1-2-3-4 piston, parking rod assembly, etc will need to be updated on overhaul.
