My 04 yukon started having a shifting issue I can't find anywhere in any forum. It will not shift to 2nd gear 1,3,4,tcc all working fine and shifting normal as they always have. I first assumed a bad shift solenoid, I found a schematic showing how the 2-3 shift circuit would close the 1-2 solenoid, I then thought maybe a broken spring in the actuator. Well today I was in a hurry to get home and on a long stretch of highway opened it up. When the speedometer hit 100 I expected it to shut down as the governor on these trucks are set at 100 mph, but it didn't it kept climbing I let off the throttle at 115 and decided I should look into why. Is it possible the transmission control module is junk? Maybe this is causing my whole issue. Anyone else ever experienced this problem or know if the transmission control module also controls the governor on these trucks?