Just read about someone's rear diff "groaning" and having issues. I was getting my oil changed at Valvoline and the guy tried to tell me I was due for rear diff fluid change. My car has 45K miles on it, and the maintenance interval on the rear diff looks really aggressive to me (every 15K?). Is this true? Is this something I should service? I bought the car with 42K miles and have no idea when this was last done.

 

YOu sure about that 15K miles ? AFAIK, it is a sealed for life fill.

 

Whose maintenance interval? If it was a schedule created by the lube shop it's only ok for use in outhouses.