Go to the gun store and buy a bottle of Triflon. It's a non-petroleum teflon based lube. That's the best stuff I've used.

You need to tear the bow completely down, clean everything, inspect for wear and relube at least every two years. I would hope Browning would have done that for you when they replaced the limbs and axles. It's not likely they replaced the bearings unless they were obviously worn out, so it's possible you've got a bad bearing.

It's also possible that you've simply got a couple dry spacers rubbing against each other. If that's the problem, then the Triflon will fix it. If it's a bad bearing... Well, now's the time of year to get the bow in the shop and have it fixed.