Heat is the enemy of a 68RFE Transmission! We like to see our builds stay between 150-170 degrees with light towing/normal driving. The most cost effective way to achieve those numbers before spending $5k+ on a new transmission, would be to bypass the factory thermostat block on the transmission lines. 

There is zero resistance in our Bypass. The fluid flows directly to the transmission then to the cooler exactly where it should be sent. The OE Bypass is known for continuously failing, causing hot fluid to recirculate back into the transmission. Which could result in transmission failure.