There is a roaring sound in my chevy blazer when travling, I replaced the front right wheel hub assemvly and the roaring is still there. What elese could be the problem?

Yeah that's what I thought to, but the sound is still there. I had the truck in the shop in May and it had an axle seal blown causing it to smoke real bad on right rear wheel. They put a new axle seal in and replaced the caliper because the oil had stuck the caliper and messed it up. I jacked up the truck under the rear end. With both tires off the ground I put in in drive no sound. I put transmission in reverse and still no sound. I checked the play in all four wheel hub assemblys and found no play. Is there any thing elese it could be. Its only roars when moving. Yeah that's what I thought to, but the sound is still there. I had the truck in the shop in May and it had an axle seal blown causing it to smoke real bad on right rear wheel. They put a new axle seal in and replaced the caliper because the oil had stuck the caliper and messed it up. I jacked up the truck under the rear end. With both tires off the ground I put in in drive no sound. I put transmission in reverse and still no sound. I checked the play in all four wheel hub assemblys and found no play. Is there any thing elese it could be. Its only roars when moving.