Help!!! I have a 1990 Chevy Sportside 4wheel drive truck. It has a 383CI, 370HP & 410 torque, 1-5/8 headers, 3:42 gear ratio, 31.5 tire diameter & a 700R4 with a deep pan. I can't find the reason the transmission is running hot & failing. Before the new engine was installed the trans. was sent to the local trans. shop for beefing up & a JW Performance lock-up converter 1900 stall was installed. The trans. failed after 3000 miles. Again they rebuilt it & all the lines were flushed. I installed a temperature gauge in the truck with the pickup in the rear of the trans. pan, at the same time a Perma-Cool cooler with a fan was installed. The trans. was installed with another new converter & after 30 minutes of driving the temp. was at 240 degrees. They again went thru the trans. but with the same results. The TV cable & geometry was verified to be correct. The shop no longer new what to do so I received a refund. I purchased a Raptor Level 4 from PATC with another new converter & it also ran hot & failed. Another of their trans. & converter was installed. It is also running hot but it was shut down as soon as the temp. went that high. The temp. was verified with a infrared gun, lines are clear, correct pressure at trans, 7 qts flow. We are at our wits in, no one seems to know what is going on but the entire trans. is hot. I have wondered if it could be the header heat but there is so many vehicles using headers that surely if that was the problem someone would know. If you could help me or point me to someone that could I would appreciate it.