Jester

As you guys know I installed a 3.73 posi rear this weekend that I had swapped a new (used) carrier into.

It runs great, until you get about 40 miles down the road. Then it starts making this
really awful loud as hell binding/snapping metallic sound. The car behind me could hear it with his windows rolled up and AC on. When it first started I thought for sure it was
teeth shearing off the gears. It makes a pop/bang about every 2 feet at most. I waited
till it cooled off (I was at work when this happened) and pulled the cover, and everything looked perfect. Turned smooth and easy as it should...no gear damage or anything. Then about 40 miles into my drive home it started again. I'm too tired to pull the cover again tonight and look while it's doing it. you guys have any ideas?

I got the posi carrier out of a 4th gen rear that had chewed up the gears. I had assumed it was from a failed pinion bearing...the posi has no damage at all as far as I can see

Oh yeah...it's not just a sound..you can feel it jerk a bit too.

and it's only doing it at low speeds.

Superman

What kind of grease did you use?Did you use posi gear additive with the grease?I had a rear end do that same thing once and I switched the grease amsoil and it stoped it.Don't know if it will work for ya,just a thought.