2012 AWD trans axle/differential smoking

Trans axel or front diff burning oil smell. I had this smell and my mechanic changed fluids/filter in trans and both differentials ( AWD). Now the smell is of new fluid burning. I have read post about gen2 front diff seals leaking and losing all the fluid without you knowing it till its too late. motor oil is in good shape and doesn't seem to be a burning oil smell. Smoke is not visible from any components. Before fluid change front wheels were a tad grumpy when turning at slow speeds. Once at high speed freeway clover leaf it nearly shutdown with a bunch of idiot lights. ohh old trans oil was black an nasty. 178k miles Thanks Tom