What might cause jeep wrangler front differential leak?

The most common reason You'll find that Your Jeep Wrangler's front differential springs a leak is deteriorated quality in the seals. Especially if they're older, it's possible that internal sludge has kept the fluid in for a period of time, up until they begin to fail. You may see people mentioning flexing as a cause of leaks, but this typically is not the case; if the seals are working properly, flex is accounted for. With that said, it's important to keep a vigilant eye on Your differential fluid levels, especially if You determine that there's a leak. It's wise to replace all of the seals (front and rear), since if one is beginning to fail, they likely all will soon -- assuming they're around the same age.