2010 F150 Front and Rear Differential Fluid

[fordtough87]

I was planning on flushing my front and rear differential fluids and the guy at NAPA told me that my rear axle takes SAE 75W-140 synthetic real axle gear oil. He also told me that rear axles containing synthetic oil are lubricated for life, unless there is a leak detected. Do not check or change. Is this correct, should I not flush my rear differential fluid?

[2004XLT5.4LTritonV84X4]

I'm not 100% sure, but on a a dif. I wouldn't think you'd need to flush it on a 2010...unless you 100,000+ miles on it. However, if you want to, I don't think it's a problem either.....unless it's barely broken in or something. Look into it a little more though, don't just take my best guess and go do it! :D Good luck man!