Hi guys, I am wondering if we need friction modifier added to our differentials when changing the fluid. my factory build sheet says conventional differentials on front and rear. doesn't look like i have limited slip then? 2011 Durango citadel hemi AWD with tow package. Also i was looking at two different part numbers from mopar with the same 75w-85 synthetic fluid. 05136035AB and 68210057AB. looks like its the same fluid?