Ok, So I was hauling wood yesterday and when I get on it in second gear I hear a whoob whoob whoob and alittle shaking. I can hardly hear it with the motor running, so I drove a long and shut the motor and rolled in neutral and it does it about 3-4 times per tire revolution. I just can't get close enough to hear it, sounds almost from the joint closest to the T case. Thoughts

 

Set your parking brake, block the wheels good, put the trans in neutral and start reefing on the driveline. Should find some looseness or something if you have a bad joint.

 

Bad joint at the rear position.