Hit the speed bumps at work today. If only one sides hits hit, it doesn't make the noise. If both sides hit then it makes the sound. I read the other post and it seems like you guys had some miles on the truck w/ some kind of lift. It's Brand new w/ stock suspension parts. The only part that bites is there is only a little Nissan shop here. The big one is 30-45 min. drive.
Dropped the truck off at the shop yesterday. Actaully got it to make the sound on the test drive. The service manager said that he would make some phone calls and see what's up. Calls me back a little later and said that the other shop had seen some w/ the body mounts loose. The service manager from the other shop called me and told me that they thought the noise was coming from the passenger side. Turns out that the Passenger front body mount was 3 full turns loose.
Get her back today and took a back road home. Still made a popping sound but i don't think it was that bad. Tomorrow will be the test though. Get to go over the speed bumps at work. These seem to be the only speed bumps that i can get it to make the noise over.
You say on rebound...which would be just after the compression of the shock or spring after the front end comes back down after your bump. If that's exactly what you mean, I don't have that problem...
My pro4x's front suspension (oem Rancho) definitely makes noise (like a clunk) on the initial rise of the front end after a speed bump, but i'm fairly sure it's the shock or spring running out of travel... don't know if this happens with aftermarket suspension. I certainly never had this problem with any car I've driven, but I'm sure the additional mass / momentum and softer suspension of the truck makes a difference.
Ok, Stock truck, stock suspension, stock body. NO body lift, NO suspension upgrades. NO aftermarket wheels/ tires.
It is probably just a normal noise, due to the lack of travel in the stock suspension. These truck only have like 5-6" of travel. If taken over a speed bump of good size, the suspension will droop all the way out. All you are probably hearing is the droop stop. Since the body mount was a little loose, and is now tightened and you still have the noise.