I was gonna change my diff fluid today and noticed on the cover that it will only take 75W-140.....damn it!!!! I bought 75W-90 of Royal Purple gear oil! Do I still have to use 140???? Just wondering, I'm gonna go back and return the oil and see if they have the 140 in-stock....wish me luck. Should I go with the Mobile 1...the only oil there with 75w-140....or the Royal Purple....75w-140??
