Chosen Solution

My rear diff oil is black and smells almost immediately after changing it to fresh recommended oil. The previous owner I believe never changed it but I have had it changed twice in the past two days. both times it was black with only a 30 minute ride. Also after driving on a dip the howling sound started and has not stopped even after the diff oil changes and a center barring mount change. pls help

Unless you clean out all the old oil and the carbon build up off all the parts the oil is going to change rather quickly. If you’ve changed diff parts and are getting a howling sound you might need to change the shims as the backlash may need to be adjusted.