GreenMachine14

Hello all, I'm new on this forum. I have a 2014 Silverado 1500 with the L83 5.3L and the 6l80. Performance wise I have a Cold Air Inductions cold air intake installed, cat-back dual straight pipes, and it's dyno-tuned with HP-Tuners and AFM is disabled. It makes 374hp to the wheels. Also I have 135,000 miles on the truck. I'd also like to mention I'm the 2nd owner. I do a lot of highway driving with the truck and at highway speeds several months ago I noticed it started shifting funny. Sometimes it's like it doesn't know what gear it should be in or it can't find the next gear. As of the past month I've been frequently checking the trans temp and at highway speeds I've noticed it climbs to as high as 212 degrees. I'm a member of several Facebook groups discussing the 2014 and up Silverados and Sierras and I've noticed many complaints about high trans temps and torque converters going out because of this high heat. I would also like the add that I have service records from the pervious owner and the trans fluid had been previously flushed. I'm wondering what kind of experiences you on here have with some of the solutions to these high temps? Have any of you deleted the trans cooler thermostat? Have any of you installed the Sure Cool system? Have you installed an aftermarket external trans cooler? Also do you think based on what I described with the way it shifts that the problem could be something deeper in addition to the high temperatures? Any feedback would be greatly appreciated!