front differential output bearing

I have posted this question elsewhere on this forum and have not gotten an answer as of yet. I apologize in advance if reposting here is an issue with the mods. I have a 2003 330xi with 150,000 and I am chasing a driveline vibration that occurs @ 2300-2500 rpm. It felt as though the vibration was happening from center of the car back. I had the tires rebalanced and alignment checked. I have replaced motor mounts, giubo, csb, tx case mount, changed all fluids in both diff's and tx case, and a trans filter and fluid change. All of these made a short term improvement before the vibration returned. Last week I replaced both front axles with A1 cardone remans. When I pulled the seal from the drivers side output on the differential I tried to rotate the roller bearing and it did not seem to rotate. I cleaned the area with a clean rag to check for any scoring or discoloration of the bearing and there was none nor was there any scoring on the shoulder of the old cv axle. Not knowing all that much about differentials I reassembled everything so that I could check the other side. Well of course the other side is a ball bearing and rotated freely. My question is if this is normal? Although 90% of the vibration is gone I still have a slight identical vibration @ the same rpm's just not near as severe as it was before the axle replacement. Please help.