Mwalabama

I ended up using a Hayden 679 and made some custom brackets out of steel. My truck has the active shutters so I fit it behind the radiator bracket in front of the radiator.

Hi all, To follow up, I flushed all the lines, even bypassed the thermostat completely to see if any difference was made. Nope, none.. After a trip where the trans temp got up to 210 pulling my 17’ Key west center console boat (guessing 3500lbs loaded) in 83’ ambient temps on mostly level ground, I decided to add an additional aftermarket trans cooler in line after the factory cooler. yesterday I towed the same boat on the same drive, 97’ ambient temps with 95% humidity, temps stayed south of 170 even in standstill traffic and rolling 80 on the highway on 35s. with no trailer it stays floating around the 140-150 degree area even in 90+ temps.

Folks with the 159’ trans thermostat, over long drives does your trans temp still climb well over the 160 mark? I drove my 17 Sierra 220 miles today and by the end of the drive it had reached 180’ in 80 degree ambient temps. I would like to think the cooling system is efficient enough to keep it lower..?.. The condenser/trans cooler was replaced a while back, but this issue happened before that. Once I parked and let it idle, it dropped to 165 in 15 minutes. I’m not concerned right now, but I will be when it gets too 100’f out (Alabama weather, yay) and I’m pulling my boat to the beach or my other truck to and from the track on the flatbed. Do y’all think I’m missing something here and I have some issue? Or is this the standard and I need to just add an external cooler? When I first swapped the 159 thermostat( when the new trans was put in) the temps stayed at 145 all the time, but it hasn’t been that way in quite a while. I even pill flipped it and all that did was make it take forever to warm up but to the same effect. Full system fluid change was done about 1k miles ago with oem filter and ac delco dex6 fluid. Trans has around 47k on it. Truck has about 127k on it. Do y’all think I’m missing something here and I have some issue? Partially plugged line? Or is this the standard and I need to just add an external cooler? Any help would be appreciated at this point..