I have a 2002 Trailblazer 4.2 I6. The 4WD and A4WD are both not engaging. Brought to a mechanic who is my wife's cousin and he said the problem is likely with the front differential and recommended another shop with lower hourly labor costs. He told me the motor that engages the 4WD is working fine. The front axle does engage but both cv shafts do nothing. Also there was a clicking sound from the front passenger side wheel when he spun it on the lift. He also pointed out that the front differential was hot to the touch which scares me
. It makes no strange noises while driving and still gets the same MPG as it always has. How dangerous is it to drive this way and does it sound like the differential will need replacement? I thank you for reading and welcome any help or suggestions.