if its a toyota i would check it because it has a breather on the top of the axle on left side just to be sure easy preventive maintance and if your towning alot it doesnt hurt to change it check your factory schuedule maintance for your vehicle should tell you when to change it for towing

It is a yota I will look for that breather thanks!

also, if those breathers get clogged they can cause axle shaft seal leaks. you'll see differential fluid starting to seep out behind the brakes. just an fyi...