Hi all 1st post here been looking thru forums to try and solve my issue tried a few but still having problem, here are the symptom’s I’m getting 2005 slt envoy with awd/4hi/4low I can hear the transfer motor whirl when I select any of them and it feels like a slight bump when it engages. Recently when I tested the awd and 4hi getting ready for rural Ontario Canada winter driving the car seemed to labour and groaning noise from front end could be heard, put it on ramps and noticed oil near front diff found the drain bolt to be loose (fingers undid it) so drained and refilled with correct grade oil. Tried awd/4hi on driveway seemed ok but decided to try at hiway speed 70km same thing happened groaning from front end and bogging down the engine speed. It’s dark here at this time but will put back on ramps in the morning and check for leakage again and update if there is any. Has anyone else come across this problem and what was the fix thanks in advance to everyone who answers.