hey all, new here, tried searching but wasn't coming up with any thing, i have an 04 Silverado 4x4, 5.3 with the push button 4x controls, whey i put in 4wd hi or low truck stays in 2wd, lights on button light up to whatever selection i chose, ive changed both the front axle shaft motor and transfer case motor, when in 4x the front drive shaft does stop spinning freely so it is engaging just unsure if its the front axles engaging or the dif, any ideas?