I have a Cat 977L 11K5351 that the transmission oil is overheating after about 3 hours of use (in the summer). It appears that there is no oil flowing to the oil cooler beside the radiator as I used a laser temp gun and it showed about 110 degrees and the transmission housing was around 235 degrees. Is there a thermostatically controlled bypass on the cooler lines? I looked but couldn't see anything. Let me know if you all have any ideas and thank you for your help.
The attached may be of some help. The inlet to the powertrain oil cooler comes from the torque converter outlet relief valve.