I use Castrol Syntec 5w50 and change it when I feel like it (15k, 17k, 20k, whenever). I don't really track it.

 

Question for those of you using RP in your diffs...are they open differentials? From what I've read RP has friction modifiers for LSD already mixed with the oil. Would this be bad to put in the open diff?

 

I run Royal Purple in my front and rear diff but I have a LSD atleast in the rear. Not sure whats in the front.

 

You have an open diff in the front (unless someone added an aftermarket limited slip or a locker ... doubtful).

zique: Having friction modifier in your diff fluid won't hurt anything.

 

synthetic in the rears is the best thing ever i have BG in mine for like 75k and is still looks great and doesn't smell burnt
I have not tried the RP but its made in porter TX so icant be bad

 

ive been running royal purple in all my drivetrain for a little over a year i love it....

 

Its synthetic oil guys, change the filter at manufacturers intervals, usually 7,000 miles and use a good synthetic fibriousfilter media not that cheap pos fram filter, they suck period. I use Amsoil full synthetic and dont change my oil for atleast 15-20,000 miles and Amsoil says 25-35,000 or 1 year whatever comes first. If you want the extra insurance, take an oil sample and send it out for analysis and see what they recommend on changing the oil, only costs around 20 bucks...... if you guys want to try Amsoil, I am a dealer but I usually buy it for myself............Dallas

 

I still like the idea of chaning it every 5k even with Royal Purple. I've been running Purolator premium filters on my Ram and K&N on my Honda. I'm not too sure whats good other than knowing Fram is crap.

 

mobile1., pure1, bosch, donaldson,factory filters and believe it or not, the walmart supertec filters or carquest filters

 

How often do you guys change the diff fluid with RP in? Thats one thing I don't know how often I should change even with stock fluid in there.