Bpand2

I have a 2005 F150 Lariat Supercrew 4x4 with a 5.4L. For a few weeks now I have been hearing a ticking noise. It only happens when in gear and moving under load. Tonight I jacked up the rear end, put jackstands and blocked the front tires. It did not make the noise. I then removed the jack stands and blocked the front and rear tires. I put in gear and put it under load as much as I could without slinging the blocks. No noise. I then lowered it and drove it. No more noise. I am thinking it will return because I didn't do anything to fix. I Mitch add that I know I need a new starter as I am getting the screaching noise when cranking. However I don't think that is related. I also should note that the truck has that familiar Ford clunking noise when you accelerate from a stop. I understand this is driveshaft/yolk related. I also don't think this is related. Could it be a u-joint problem and somehow blocking it up temporarily made the noise go away? Also thought maybe a catalytic converter rattle? Unfortunately I can't get it to duplicate the issue and get under it to see exactly where the noise is coming from. I actually gave a skateboard and strap a quick thought but too old and wise for that. Any ideas appreciated. Thanks.