Its about -35 c out... works out to like -24 F. Put my truck into 4x4 high and heard a pop/clunk noise and when my front wheels spin on ice the front left hub makes a grinding type noise. Never had any problems aslong as ive owned my truck. I dont think the left front wheel is completely engaging seems like its trying to but just grinds

 

So my truck did something similar. I had a grinding noise then a pop. My right front wheel grinds, my left front wheel is engaged on the haft shaft. Did you find out what was wrong with yours?

 

Vacuum line wasnt working 100%

 

is your drive shaft disengage on 2 wheel drive while the engine running? if one is ,,, you got a Hub actuator problem on that one , and the grinding is on the other side .that is a solenoid problem. Solenoid is around $19 - 30 . Hub is $60 online -local parts store is around $120 .easy fix.

 

I did a vaccum test and tore apart my hubs. I found a bad IWE actuator on the passenger side. Also found that it destroyed my hub assembly on the drive home.