I don't know what kind of differential fluid I have in terms of synthetic or not. Would it be a problem to replace the fluid with royal purple 75w90 synthetic gear oil? I know that people do this, but I didn't know if I need to know if what's already in the gears is synthetic or not.
Thanks

 

*sigh*

I am TRYING to be nice.

but seriously, there are like thousands of threads asking the exact same question. would you mind to search ?

 

just change the diff oil, it only takes 1.3-1.4 qt. you could use royal purple 75w90 that's what I use...

 

thank you, that helped