Noise in rear

Now that I have my rear main seal leak and front diff o-ring fixed... something else comes up.
I first noticed this a few weeks ago after I had to stop kinda hard...
I am having a "popping" noise coming from what sounds like my rear diff. I have Rusty's 3" lift on it, and have for about 1 year now. I do have vibes that I've not been able to get rid of, and I am probably shortly getting a SYE, but I don't have the cash at the moment. Any idea what this sound could be? I want to say it sounds like a binding sound, but it goes away after a you get to like 2000RPM, it only does it after I stop, and then right when I take off again. Also, it doesn't happen everytime I stop, but it is getting more often.
Thanks.

Sounds like the U-joint to me. If your already dealing with vibration, it stands to reason that the joint may be on it's way out. Get under there and check it for over play or slop. The SYE will be great for the other end of the driveshaft, but won't help your current situation. I'm sure other members will be able to provide some more information and ideas.